docs(operations): split scanner excess alerts into English and Chinese pages

The page shipped Chinese-only; keep it as scanner-excess-alerts_zh.md and
add a faithful English translation at the original path, cross-linked at
the top of both.

Co-Authored-By: heihutu <heihutu@gmail.com>

Cargo.lock

@@ -9825,14 +9825,19 @@ name = "rustfs-madmin"
 version = "1.0.0-rc.2"
 dependencies = [
  "hotpath",
+ "http 1.5.0",
  "humantime",
  "hyper",
  "jiff",
+ "reqwest",
  "rmp-serde",
+ "rustfs-signer",
+ "s3s",
  "serde",
  "serde_json",
  "sysinfo",
  "time",
+ "tokio",
 ]
 
 [[package]]
@@ -10246,6 +10251,7 @@ dependencies = [
  "rustfs-ecstore",
  "rustfs-filemeta",
  "rustfs-lock",
+ "rustfs-s3-types",
  "rustfs-storage-api",
  "rustfs-utils",
  "s3s",

_typos.toml

@@ -40,6 +40,7 @@ mak = "mak"
 gae = "gae"
 GAE = "GAE"
 thr = "thr"
+mis = "mis"
 # s3-tests original test names (cannot be changed)
 nonexisted = "nonexisted"
 consts = "consts"

crates/ecstore/src/api/mod.rs

@@ -373,14 +373,14 @@ pub mod error {
 
 pub mod erasure {
     pub use crate::erasure::coding::{
-        BitrotReader, BitrotWriter, BitrotWriterWrapper, CustomWriter, Erasure, ErasureConstructionError, ReedSolomonEncoder,
-        calc_shard_size, calc_shard_size_legacy,
+        BitrotReader, BitrotSelfTestError, BitrotWriter, BitrotWriterWrapper, CustomWriter, Erasure, ErasureConstructionError,
+        ReedSolomonEncoder, bitrot_self_test, calc_shard_size, calc_shard_size_legacy,
     };
 }
 
 pub mod event {
     pub use crate::event::name::EventName;
-    pub use crate::services::event_notification::{EventArgs, register_event_dispatch_hook};
+    pub use crate::services::event_notification::{EventArgs, register_event_dispatch_hook, send_event};
 }
 
 pub mod global {

crates/ecstore/src/erasure/coding/bitrot.rs

@@ -820,10 +820,263 @@ impl BitrotWriterWrapper {
     }
 }
 
+// --- startup bitrot self-test (rustfs/backlog#1873, MinIO bitrotSelfTest parity) ---
+//
+// A broken hash implementation (bad SIMD feature combination, platform drift, a
+// key-handling regression) fails silently: every shard reads back "corrupt",
+// heal rewrites data that was fine, and cross-platform clusters disagree about
+// which copy is healthy. The self-test below pins the algorithms the moment a
+// process starts, so a drifted build announces itself instead of quietly
+// rewriting objects. See docs/rustfs-heal-scanner-vs-minio-comprehensive-
+// analysis-2026-08-16.md §6 HS-11.
+
+/// Length of the deterministic self-test payload.
+pub const BITROT_SELF_TEST_PAYLOAD_LEN: usize = 4096;
+
+/// Known-answer digest of [`bitrot_self_test_payload`] under `HighwayHash256S`
+/// (the production default). Pinned so any platform or build where the
+/// implementation drifts fails startup instead of miss-hashing shards.
+const BITROT_SELF_TEST_KAT_HIGHWAY_HASH256S: [u8; 32] = [
+    0xb9, 0x32, 0xa2, 0xaa, 0x4a, 0xb7, 0x33, 0x6a, 0xa3, 0xca, 0x7e, 0x61, 0x9d, 0x86, 0x52, 0x14, 0x6e, 0x7f, 0xd8, 0x9e, 0xea,
+    0x08, 0xd9, 0x8c, 0x33, 0x85, 0x87, 0x19, 0x30, 0xd6, 0xed, 0x06,
+];
+
+/// Known-answer digest of the same payload under `HighwayHash256SLegacy`.
+const BITROT_SELF_TEST_KAT_HIGHWAY_HASH256S_LEGACY: [u8; 32] = [
+    0x98, 0x24, 0x71, 0x4f, 0x16, 0xbb, 0x48, 0x39, 0xed, 0x68, 0xfa, 0x63, 0x5e, 0xd9, 0x07, 0x61, 0xdf, 0x0a, 0xff, 0xcf, 0x7d,
+    0x8c, 0xa8, 0xc7, 0xc0, 0xb6, 0x6f, 0x05, 0xdb, 0xda, 0x5a, 0x22,
+];
+
+/// FIPS 180-2 test vector: SHA-256 of the ASCII string "abc". Unlike the
+/// Highway digests above this one is externally verifiable, so it guards the
+/// whole `HashAlgorithm` plumbing even for readers who distrust pinned
+/// self-computed constants.
+const BITROT_SELF_TEST_KAT_SHA256_ABC: [u8; 32] = [
+    0xba, 0x78, 0x16, 0xbf, 0x8f, 0x01, 0xcf, 0xea, 0x41, 0x41, 0x40, 0xde, 0x5d, 0xae, 0x22, 0x23, 0xb0, 0x03, 0x61, 0xa3, 0x96,
+    0x17, 0x7a, 0x9c, 0xb4, 0x10, 0xff, 0x61, 0xf2, 0x00, 0x15, 0xad,
+];
+
+/// Deterministic self-test payload: xorshift64* from a fixed seed, so every
+/// platform and every run hashes the same 4096 bytes.
+fn bitrot_self_test_payload() -> [u8; BITROT_SELF_TEST_PAYLOAD_LEN] {
+    let mut state = 0x9E37_79B9_7F4A_7C15u64;
+    let mut payload = [0u8; BITROT_SELF_TEST_PAYLOAD_LEN];
+    for byte in payload.iter_mut() {
+        state ^= state >> 12;
+        state ^= state << 25;
+        state ^= state >> 27;
+        *byte = state.wrapping_mul(0x2545_F491_4F6C_DD1D) as u8;
+    }
+    payload
+}
+
+/// Why a bitrot self-test failed.
+#[derive(Debug)]
+pub enum BitrotSelfTestError {
+    /// A known-answer digest mismatched the pinned constant.
+    KnownAnswerMismatch {
+        algorithm: &'static str,
+        got: String,
+        want: String,
+    },
+    /// A freshly encoded shard failed `bitrot_verify`.
+    RoundtripVerify { algorithm: &'static str, detail: String },
+    /// A verified roundtrip read back different bytes than were written.
+    RoundtripReadback { algorithm: &'static str },
+    /// A deliberately tampered shard was not rejected by `bitrot_verify`.
+    TamperNotRejected {
+        algorithm: &'static str,
+        tampered: &'static str,
+    },
+}
+
+impl std::fmt::Display for BitrotSelfTestError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::KnownAnswerMismatch { algorithm, got, want } => {
+                write!(f, "known-answer mismatch for {algorithm}: got {got}, want {want}")
+            }
+            Self::RoundtripVerify { algorithm, detail } => write!(f, "{algorithm} roundtrip shard failed verification: {detail}"),
+            Self::RoundtripReadback { algorithm } => write!(f, "{algorithm} roundtrip read back different bytes"),
+            Self::TamperNotRejected { algorithm, tampered } => {
+                write!(f, "{algorithm} tampered shard ({tampered}) was not rejected")
+            }
+        }
+    }
+}
+
+impl std::error::Error for BitrotSelfTestError {}
+
+fn self_test_hex(bytes: &[u8]) -> String {
+    rustfs_utils::hex(bytes)
+}
+
+// (kept as a named one-liner so every KAT failure site reads the same; the
+// underlying formatter is the shared `rustfs_utils::hex`)
+
+/// Compare a digest against its pinned constant. Split out so a test can drive
+/// it with a wrong constant and prove the mismatch path fires.
+fn bitrot_kat_check(
+    algorithm: &'static str,
+    algo: &HashAlgorithm,
+    payload: &[u8],
+    expected: &[u8; 32],
+) -> Result<(), BitrotSelfTestError> {
+    let digest = algo.hash_encode(payload);
+    let digest = digest.as_ref();
+    if digest.len() != expected.len() || digest != expected.as_slice() {
+        return Err(BitrotSelfTestError::KnownAnswerMismatch {
+            algorithm,
+            got: self_test_hex(digest),
+            want: self_test_hex(expected),
+        });
+    }
+    Ok(())
+}
+
+/// Encode `payload` with `shard_size` blocks, verify it end to end, and read
+/// every block back through `BitrotReader` comparing bytes.
+async fn bitrot_roundtrip_check(
+    algorithm: &'static str,
+    algo: HashAlgorithm,
+    payload: &[u8],
+    shard_size: usize,
+) -> Result<(), BitrotSelfTestError> {
+    let mut writer = BitrotWriter::new(std::io::Cursor::new(Vec::<u8>::new()), shard_size, algo.clone());
+    for chunk in payload.chunks(shard_size) {
+        writer
+            .write(chunk)
+            .await
+            .map_err(|err| BitrotSelfTestError::RoundtripVerify {
+                algorithm,
+                detail: format!("encode failed: {err}"),
+            })?;
+    }
+    let encoded = writer.into_inner().into_inner();
+
+    let on_disk = bitrot_shard_file_size(payload.len(), shard_size, algo.clone());
+    if encoded.len() != on_disk {
+        return Err(BitrotSelfTestError::RoundtripVerify {
+            algorithm,
+            detail: format!("encoded {} bytes, size formula says {on_disk}", encoded.len()),
+        });
+    }
+    bitrot_verify(std::io::Cursor::new(encoded.clone()), on_disk, payload.len(), algo.clone(), shard_size)
+        .await
+        .map_err(|err| BitrotSelfTestError::RoundtripVerify {
+            algorithm,
+            detail: err.to_string(),
+        })?;
+
+    let mut reader = BitrotReader::new(std::io::Cursor::new(encoded), shard_size, algo, false);
+    let mut offset = 0usize;
+    while offset < payload.len() {
+        let want = shard_size.min(payload.len() - offset);
+        let mut buf = vec![0u8; want];
+        let read = reader
+            .read(&mut buf)
+            .await
+            .map_err(|err| BitrotSelfTestError::RoundtripVerify {
+                algorithm,
+                detail: format!("read back failed at offset {offset}: {err}"),
+            })?;
+        if read != want || buf[..read] != payload[offset..offset + read] {
+            return Err(BitrotSelfTestError::RoundtripReadback { algorithm });
+        }
+        offset += read;
+    }
+    Ok(())
+}
+
+/// Flip one byte and require `bitrot_verify` to reject the result.
+async fn bitrot_tamper_check(
+    algorithm: &'static str,
+    algo: HashAlgorithm,
+    payload: &[u8],
+    shard_size: usize,
+    tampered: &'static str,
+    flip_at: usize,
+) -> Result<(), BitrotSelfTestError> {
+    let mut writer = BitrotWriter::new(std::io::Cursor::new(Vec::<u8>::new()), shard_size, algo.clone());
+    for chunk in payload.chunks(shard_size) {
+        writer.write(chunk).await.expect("self-test encode should not fail");
+    }
+    let mut corrupt = writer.into_inner().into_inner();
+    let flip_index = flip_at % corrupt.len();
+    corrupt[flip_index] ^= 0x80;
+
+    let on_disk = bitrot_shard_file_size(payload.len(), shard_size, algo.clone());
+    match bitrot_verify(std::io::Cursor::new(corrupt), on_disk, payload.len(), algo, shard_size).await {
+        // The flipped byte must be rejected as a hash mismatch specifically, not
+        // by any incidental read error: an in-memory cursor cannot fail reads,
+        // so accepting any other failure here would mask a verify path that
+        // errors out before it ever compares hashes.
+        Err(err) if err.to_string().contains("hash mismatch") => Ok(()),
+        Ok(()) => Err(BitrotSelfTestError::TamperNotRejected { algorithm, tampered }),
+        Err(err) => Err(BitrotSelfTestError::RoundtripVerify {
+            algorithm,
+            detail: format!("tampered shard rejected with an unexpected error: {err}"),
+        }),
+    }
+}
+
+/// Verify every bitrot algorithm this crate can write or verify in production:
+/// both streaming Highway variants roundtrip end to end (encode → size formula
+/// → `bitrot_verify` → read back) and reject a flipped byte in both the data
+/// and the leading hash, while all three hashed algorithms reproduce their
+/// pinned known-answer digests.
+///
+/// Runs in well under a millisecond on 4 KiB of data; callers may run it inline
+/// at startup. Pure CPU, no allocation beyond a few KiB of scratch.
+pub async fn bitrot_self_test() -> Result<(), BitrotSelfTestError> {
+    let payload = bitrot_self_test_payload();
+
+    // Externally verifiable vector first: it guards the HashAlgorithm plumbing
+    // itself, before any self-pinned constants are consulted.
+    let abc = HashAlgorithm::SHA256.hash_encode(b"abc");
+    if abc.as_ref() != BITROT_SELF_TEST_KAT_SHA256_ABC.as_slice() {
+        return Err(BitrotSelfTestError::KnownAnswerMismatch {
+            algorithm: "SHA256",
+            got: self_test_hex(abc.as_ref()),
+            want: self_test_hex(&BITROT_SELF_TEST_KAT_SHA256_ABC),
+        });
+    }
+
+    bitrot_kat_check(
+        "HighwayHash256S",
+        &HashAlgorithm::HighwayHash256S,
+        &payload,
+        &BITROT_SELF_TEST_KAT_HIGHWAY_HASH256S,
+    )?;
+    bitrot_kat_check(
+        "HighwayHash256SLegacy",
+        &HashAlgorithm::HighwayHash256SLegacy,
+        &payload,
+        &BITROT_SELF_TEST_KAT_HIGHWAY_HASH256S_LEGACY,
+    )?;
+
+    for (algorithm, algo) in [
+        ("HighwayHash256S", HashAlgorithm::HighwayHash256S),
+        ("HighwayHash256SLegacy", HashAlgorithm::HighwayHash256SLegacy),
+    ] {
+        // Full blocks plus a partial tail, exactly like a real part stripe.
+        let tail_len = 2 * 1024 + 333;
+        bitrot_roundtrip_check(algorithm, algo.clone(), &payload, 1024).await?;
+        bitrot_roundtrip_check(algorithm, algo.clone(), &payload[..tail_len], 1024).await?;
+        // One flipped byte in the final data block, one in the first leading
+        // hash: both must fail verification.
+        bitrot_tamper_check(algorithm, algo.clone(), &payload, 1024, "final data byte", payload.len() - 1).await?;
+        bitrot_tamper_check(algorithm, algo, &payload, 1024, "leading hash byte", 0).await?;
+    }
+
+    Ok(())
+}
+
 #[cfg(test)]
 mod tests {
     use super::{
-        BitrotReader, BitrotWriter, BitrotWriterWrapper, CustomWriter, bitrot_shard_file_size, bitrot_verify, write_all_vectored,
+        BitrotReader, BitrotWriter, BitrotWriterWrapper, CustomWriter, bitrot_kat_check, bitrot_self_test,
+        bitrot_self_test_payload, bitrot_shard_file_size, bitrot_verify, write_all_vectored,
     };
     use super::{MAX_RETAINED_CHUNKS_PER_BLOCK, ShardChunkRead, ShardSource};
     use bytes::Bytes;
@@ -1090,6 +1343,32 @@ mod tests {
         }
     }
 
+    #[test]
+    fn bitrot_self_test_payload_is_deterministic() {
+        // Two independent builds of the payload must agree byte for byte, or
+        // the pinned known-answer digests below would be meaningless.
+        assert_eq!(bitrot_self_test_payload(), bitrot_self_test_payload());
+    }
+
+    #[test]
+    fn bitrot_self_test_rejects_a_wrong_known_answer_digest() {
+        let payload = bitrot_self_test_payload();
+        let wrong = [0u8; 32];
+        let err = bitrot_kat_check("HighwayHash256S", &HashAlgorithm::HighwayHash256S, &payload, &wrong)
+            .expect_err("a zeroed digest must never match");
+        match err {
+            super::BitrotSelfTestError::KnownAnswerMismatch { algorithm, .. } => assert_eq!(algorithm, "HighwayHash256S"),
+            other => panic!("expected KnownAnswerMismatch, got {other:?}"),
+        }
+    }
+
+    #[tokio::test]
+    async fn bitrot_self_test_passes() {
+        bitrot_self_test()
+            .await
+            .expect("the pinned digests and roundtrip checks must all pass on this platform");
+    }
+
     #[tokio::test]
     async fn vectored_test_writers_cover_fallback_flush_and_shutdown_paths() {
         let mut counting = VectoredCountingWriter::default();
@@ -1189,7 +1468,7 @@ mod tests {
         let last = corrupt.len() - 1;
         corrupt[last] ^= 0x80;
         let err = bitrot_verify(
-            Cursor::new(corrupt),
+            std::io::Cursor::new(corrupt),
             super::bitrot_shard_file_size(data.len(), shard_size, algo.clone()),
             data.len(),
             algo,
@@ -1282,7 +1561,7 @@ mod tests {
 
     #[tokio::test]
     async fn bitrot_reader_rejects_output_buffers_larger_than_shard_size() {
-        let mut reader = BitrotReader::new(Cursor::new(Vec::<u8>::new()), 4, HashAlgorithm::None, false);
+        let mut reader = BitrotReader::new(std::io::Cursor::new(Vec::<u8>::new()), 4, HashAlgorithm::None, false);
         let mut out = [0u8; 5];
         let err = reader
             .read(&mut out)
@@ -1407,7 +1686,7 @@ mod tests {
             (HashAlgorithm::HighwayHash256, true),
         ] {
             let label = format!("{algo:?}");
-            let writer = Cursor::new(Vec::<u8>::new());
+            let writer = std::io::Cursor::new(Vec::<u8>::new());
             let mut w = BitrotWriter::new(writer, shard_size, algo.clone());
             w.write(&[7u8; 16]).await.unwrap();
             let written = w.into_inner().into_inner();
@@ -1492,7 +1771,7 @@ mod tests {
     }
 
     async fn encode_one_block(payload: &[u8], shard_size: usize, algo: HashAlgorithm) -> Vec<u8> {
-        let mut w = BitrotWriter::new(Cursor::new(Vec::<u8>::new()), shard_size, algo);
+        let mut w = BitrotWriter::new(std::io::Cursor::new(Vec::<u8>::new()), shard_size, algo);
         w.write(payload).await.unwrap();
         w.into_inner().into_inner()
     }
@@ -1600,7 +1879,7 @@ mod tests {
         for algo in [HashAlgorithm::HighwayHash256S, HashAlgorithm::HighwayHash256SLegacy] {
             for &size in &[1usize, 16, 17, 32, 40, 48] {
                 let payload: Vec<u8> = (0..size).map(|i| i as u8).collect();
-                let mut w = BitrotWriter::new(Cursor::new(Vec::<u8>::new()), shard_size, algo.clone());
+                let mut w = BitrotWriter::new(std::io::Cursor::new(Vec::<u8>::new()), shard_size, algo.clone());
                 for chunk in payload.chunks(shard_size) {
                     w.write(chunk).await.unwrap();
                 }
@@ -1674,14 +1953,14 @@ mod tests {
             w.write(&data).await.expect("write shard");
 
             let mut via_read = vec![0u8; SHARD];
-            let n1 = BitrotReader::new(Cursor::new(encoded.clone()), SHARD, algo.clone(), false)
+            let n1 = BitrotReader::new(std::io::Cursor::new(encoded.clone()), SHARD, algo.clone(), false)
                 .read(&mut via_read)
                 .await
                 .expect("read");
 
             // A buffer with only capacity — no initialized bytes at all.
             let mut via_append: Vec<u8> = Vec::with_capacity(SHARD);
-            let n2 = BitrotReader::new(Cursor::new(encoded), SHARD, algo.clone(), false)
+            let n2 = BitrotReader::new(std::io::Cursor::new(encoded), SHARD, algo.clone(), false)
                 .read_appending(&mut via_append, SHARD)
                 .await
                 .expect("read_appending");
@@ -1706,7 +1985,7 @@ mod tests {
             encoded.truncate(encoded.len() - 1);
 
             let mut out: Vec<u8> = Vec::with_capacity(SHARD);
-            let err = BitrotReader::new(Cursor::new(encoded), SHARD, algo.clone(), false)
+            let err = BitrotReader::new(std::io::Cursor::new(encoded), SHARD, algo.clone(), false)
                 .read_appending(&mut out, SHARD)
                 .await
                 .expect_err("a truncated shard must not succeed");
@@ -1732,7 +2011,7 @@ mod tests {
         encoded[last] ^= 0xff;
 
         let mut out: Vec<u8> = Vec::with_capacity(SHARD);
-        let err = BitrotReader::new(Cursor::new(encoded), SHARD, algo, false)
+        let err = BitrotReader::new(std::io::Cursor::new(encoded), SHARD, algo, false)
             .read_appending(&mut out, SHARD)
             .await
             .expect_err("a corrupt shard must not verify");
@@ -1844,7 +2123,7 @@ mod tests {
             "Cursor<Bytes> must be able to hand out a block, otherwise the fast path is dead code"
         );
         assert_eq!(mem.position(), 8, "taking a block must advance like a read of the same length");
-        let mut streamed = Cursor::new(encoded.clone());
+        let mut streamed = std::io::Cursor::new(encoded.clone());
         assert!(
             ShardSource::try_take_block(&mut streamed, 8).is_none(),
             "a non-Bytes source must stay on the streaming path"
@@ -1872,7 +2151,7 @@ mod tests {
         );
 
         let mut via_stream: Vec<u8> = Vec::with_capacity(SHARD);
-        BitrotReader::new(Cursor::new(encoded), SHARD, algo, false)
+        BitrotReader::new(std::io::Cursor::new(encoded), SHARD, algo, false)
             .read_appending(&mut via_stream, SHARD)
             .await
             .expect("streaming read");

crates/madmin/Cargo.toml

@@ -37,7 +37,11 @@ hotpath-cpu = ["hotpath", "hotpath/hotpath-cpu"]
 [dependencies]
 hotpath.workspace = true
 humantime.workspace = true
+http.workspace = true
 hyper = { workspace = true, features = ["http2", "http1", "server"] }
+reqwest = { workspace = true, features = ["json"] }
+rustfs-signer.workspace = true
+s3s.workspace = true
 jiff = { workspace = true, features = ["serde"] }
 serde = { workspace = true, features = ["derive"] }
 serde_json = { workspace = true, features = ["raw_value"] }
@@ -49,3 +53,4 @@ doctest = false
 
 [dev-dependencies]
 rmp-serde.workspace = true
+tokio = { workspace = true, features = ["macros", "rt-multi-thread", "net"] }

crates/madmin/src/client.rs

@@ -0,0 +1,851 @@
+// Copyright 2024 RustFS Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Admin API HTTP client for heal and scanner management (rustfs/backlog#1869).
+//!
+//! [`AdminClient`] speaks the `/rustfs/admin/v3` surface with S3 SigV4
+//! request signing (the same scheme the server's admin router authenticates),
+//! so `mc`-style tooling and automation can drive heal start/query/cancel and
+//! read background-heal / scanner status without hand-rolling HTTP.
+//!
+//! Wire structs in this module mirror the server-side shapes
+//! (`rustfs/src/admin/handlers/heal.rs`, `handlers/scanner.rs`,
+//! `rustfs-common/src/heal_channel.rs`), following the madmin-go model where
+//! the SDK owns its own copies and round-trip tests pin the encoding. Deeply
+//! nested status payloads that the server composes from runtime types are
+//! carried through as `serde_json::Value` and flattened maps rather than
+//! duplicated field-for-field, so the client cannot silently drift on fields
+//! it never interprets.
+
+use crate::heal_commands::HealResultItem;
+use http::Method;
+use serde::{Deserialize, Serialize, de};
+use std::time::Duration;
+
+/// Default admin API path prefix on a RustFS endpoint.
+pub const DEFAULT_ADMIN_API_PREFIX: &str = "/rustfs/admin";
+/// Default SigV4 region when the server has no explicit region configured.
+pub const DEFAULT_REGION: &str = "us-east-1";
+
+/// Scan mode for a heal request, mirroring the server's numeric-or-name wire
+/// encoding (`0` unknown/default, `1` normal, `2` deep).
+#[derive(Debug, Clone, Copy, Default, PartialEq, Eq)]
+pub enum HealScanMode {
+    /// Server default; behaves as [`HealScanMode::Normal`].
+    #[default]
+    Unknown,
+    /// Metadata-level checks only.
+    Normal,
+    /// Full bitrot verification while healing.
+    Deep,
+}
+
+impl HealScanMode {
+    fn wire_number(self) -> u8 {
+        match self {
+            Self::Unknown => 0,
+            Self::Normal => 1,
+            Self::Deep => 2,
+        }
+    }
+
+    fn from_wire_number(value: u8) -> Option<Self> {
+        match value {
+            0 => Some(Self::Unknown),
+            1 => Some(Self::Normal),
+            2 => Some(Self::Deep),
+            _ => None,
+        }
+    }
+
+    fn from_wire_name(value: &str) -> Option<Self> {
+        match value {
+            "unknown" => Some(Self::Unknown),
+            "normal" => Some(Self::Normal),
+            "deep" => Some(Self::Deep),
+            _ => None,
+        }
+    }
+}
+
+impl Serialize for HealScanMode {
+    fn serialize<S: serde::Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+        serializer.serialize_u8(self.wire_number())
+    }
+}
+
+impl<'de> Deserialize<'de> for HealScanMode {
+    fn deserialize<D: serde::Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
+        struct HealScanModeVisitor;
+
+        impl de::Visitor<'_> for HealScanModeVisitor {
+            type Value = HealScanMode;
+
+            fn expecting(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+                formatter.write_str("a heal scan mode number or name")
+            }
+
+            fn visit_u64<E: de::Error>(self, value: u64) -> Result<Self::Value, E> {
+                u8::try_from(value)
+                    .ok()
+                    .and_then(HealScanMode::from_wire_number)
+                    .ok_or_else(|| E::custom(format!("unknown heal scan mode number: {value}")))
+            }
+
+            fn visit_str<E: de::Error>(self, value: &str) -> Result<Self::Value, E> {
+                HealScanMode::from_wire_name(value).ok_or_else(|| E::custom(format!("unknown heal scan mode name: {value}")))
+            }
+        }
+
+        deserializer.deserialize_any(HealScanModeVisitor)
+    }
+}
+
+/// Heal options for an admin heal request (mirror of the server body type).
+/// Fields default on decode: a client should tolerate a server response whose
+/// settings object omits fields it never set.
+#[derive(Debug, Clone, Default, Serialize, Deserialize)]
+pub struct HealOpts {
+    #[serde(default)]
+    pub recursive: bool,
+    #[serde(rename = "dryRun", default)]
+    pub dry_run: bool,
+    #[serde(default)]
+    pub remove: bool,
+    #[serde(default)]
+    pub recreate: bool,
+    #[serde(rename = "scanMode", default)]
+    pub scan_mode: HealScanMode,
+    #[serde(rename = "updateParity", default)]
+    pub update_parity: bool,
+    #[serde(rename = "nolock", default)]
+    pub no_lock: bool,
+    #[serde(rename = "pool", default)]
+    pub pool: Option<usize>,
+    #[serde(rename = "set", default)]
+    pub set: Option<usize>,
+}
+
+/// Successful heal start / path-scoped cancel response.
+#[derive(Debug, Clone, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct HealStartSuccess {
+    pub client_token: String,
+    pub client_address: String,
+    #[serde(default)]
+    pub start_time: String,
+}
+
+/// Heal task status response (query, cancel-with-token, start-then-poll).
+#[derive(Debug, Clone, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct HealTaskStatus {
+    /// `running` | `finished` | `stopped` | `notFound`.
+    pub summary: String,
+    /// Failure detail for stopped tasks; empty otherwise.
+    #[serde(rename = "detail", default)]
+    pub failure_detail: String,
+    #[serde(default)]
+    pub start_time: String,
+    #[serde(default)]
+    pub settings: HealOpts,
+    #[serde(default)]
+    pub items: Vec<HealResultItem>,
+    #[serde(default)]
+    pub truncated: bool,
+    /// Live progress snapshot; the exact shape is owned by the heal runtime.
+    #[serde(default)]
+    pub progress: Option<serde_json::Value>,
+}
+
+/// `POST /v3/background-heal/status` response. Known top-level fields are
+/// typed; the flattened heal info and operations matrix pass through verbatim.
+#[derive(Debug, Clone, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct BackgroundHealStatus {
+    /// `disabled` | `uninitialized` | `idle` | `active` | `degraded`.
+    pub state: String,
+    #[serde(default)]
+    pub heal_queue_length: u64,
+    #[serde(default)]
+    pub heal_active_tasks: u64,
+    #[serde(default)]
+    pub cluster_status_complete: bool,
+    #[serde(default)]
+    pub progress: Option<serde_json::Value>,
+    /// Remaining wire fields (flattened `BackgroundHealInfo` plus the
+    /// priority-by-source operations matrix), carried verbatim.
+    #[serde(flatten)]
+    pub extra: serde_json::Map<String, serde_json::Value>,
+}
+
+/// `GET /v3/scanner/status` response, typed at the fields operators branch
+/// on; everything else passes through verbatim.
+#[derive(Debug, Clone, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct ScannerStatus {
+    pub enabled: bool,
+    /// `fresh` | `stale` | `unknown`; absent when the scanner never completed
+    /// a cycle.
+    #[serde(default)]
+    pub freshness: Option<ScannerFreshness>,
+    #[serde(flatten)]
+    pub extra: serde_json::Map<String, serde_json::Value>,
+}
+
+/// Freshness block of the scanner status response.
+#[derive(Debug, Clone, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct ScannerFreshness {
+    /// `fresh` | `stale` | `unknown`.
+    pub state: String,
+}
+
+impl ScannerStatus {
+    /// Convenience accessor for the freshness state string.
+    pub fn freshness(&self) -> &str {
+        self.freshness
+            .as_ref()
+            .map(|freshness| freshness.state.as_str())
+            .unwrap_or("unknown")
+    }
+}
+
+/// Everything that can go wrong in an admin client call.
+#[derive(Debug)]
+pub enum AdminClientError {
+    /// The endpoint URL could not be parsed.
+    InvalidEndpoint(String),
+    /// Request build/send failed (DNS, connect, timeout, body read).
+    Transport(reqwest::Error),
+    /// The server answered a non-2xx status.
+    HttpStatus { status: u16, body: String },
+    /// The response body did not decode into the expected shape.
+    Decode { message: String },
+}
+
+impl std::fmt::Display for AdminClientError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::InvalidEndpoint(message) => write!(f, "invalid admin endpoint: {message}"),
+            Self::Transport(err) => write!(f, "admin request transport failure: {err}"),
+            Self::HttpStatus { status, body } => write!(f, "admin request failed with HTTP {status}: {body}"),
+            Self::Decode { message } => write!(f, "admin response decode failure: {message}"),
+        }
+    }
+}
+
+impl std::error::Error for AdminClientError {}
+
+impl From<reqwest::Error> for AdminClientError {
+    fn from(err: reqwest::Error) -> Self {
+        Self::Transport(err)
+    }
+}
+
+/// A signed client for a RustFS admin API.
+#[derive(Debug, Clone)]
+pub struct AdminClient {
+    endpoint: reqwest::Url,
+    access_key: String,
+    secret_key: String,
+    session_token: String,
+    region: String,
+    api_prefix: String,
+    http: reqwest::Client,
+}
+
+impl AdminClient {
+    /// Build a client for `endpoint` (e.g. `http://127.0.0.1:9000`) using root
+    /// or admin credentials. Requests are SigV4-signed with the same scheme
+    /// the server's admin router authenticates.
+    pub fn new(endpoint: &str, access_key: &str, secret_key: &str) -> Result<Self, AdminClientError> {
+        let url = reqwest::Url::parse(endpoint).map_err(|err| AdminClientError::InvalidEndpoint(err.to_string()))?;
+        if url.host_str().is_none() {
+            return Err(AdminClientError::InvalidEndpoint("endpoint has no host".to_string()));
+        }
+        let http = reqwest::Client::builder()
+            .connect_timeout(Duration::from_secs(10))
+            .timeout(Duration::from_secs(30))
+            .build()
+            .map_err(AdminClientError::Transport)?;
+        Ok(Self {
+            endpoint: url,
+            access_key: access_key.to_string(),
+            secret_key: secret_key.to_string(),
+            session_token: String::new(),
+            region: DEFAULT_REGION.to_string(),
+            api_prefix: DEFAULT_ADMIN_API_PREFIX.to_string(),
+            http,
+        })
+    }
+
+    /// Attach an STS session token (signed as `x-amz-security-token`).
+    pub fn with_session_token(mut self, session_token: impl Into<String>) -> Self {
+        self.session_token = session_token.into();
+        self
+    }
+
+    /// Override the SigV4 region (defaults to `us-east-1`, matching a
+    /// region-less RustFS deployment).
+    pub fn with_region(mut self, region: impl Into<String>) -> Self {
+        self.region = region.into();
+        self
+    }
+
+    /// Override the admin API path prefix (defaults to `/rustfs/admin`).
+    pub fn with_api_prefix(mut self, prefix: impl Into<String>) -> Self {
+        self.api_prefix = prefix.into();
+        self
+    }
+
+    /// Start a heal. `bucket` empty and `prefix` empty heals the whole
+    /// deployment (requires `recursive` or a `pool`/`set` pair in `opts`,
+    /// enforced server-side); a bucket alone heals the bucket (the server
+    /// forces `recursive` for bucket heals).
+    pub async fn heal_start(
+        &self,
+        bucket: Option<&str>,
+        prefix: Option<&str>,
+        opts: &HealOpts,
+        force_start: bool,
+    ) -> Result<HealStartSuccess, AdminClientError> {
+        let body = serde_json::to_vec(opts).map_err(|err| AdminClientError::Decode {
+            message: err.to_string(),
+        })?;
+        let mut query = Vec::new();
+        if force_start {
+            query.push(("forceStart", "true".to_string()));
+        }
+        self.post_json(&heal_path(bucket, prefix), &query, body).await
+    }
+
+    /// Query the status of the heal identified by `client_token` (the token
+    /// returned by [`Self::heal_start`]) at the path it was started on.
+    pub async fn heal_status(
+        &self,
+        bucket: Option<&str>,
+        prefix: Option<&str>,
+        client_token: &str,
+    ) -> Result<HealTaskStatus, AdminClientError> {
+        self.post_json(&heal_path(bucket, prefix), &[("clientToken", client_token.to_string())], Vec::new())
+            .await
+    }
+
+    /// Stop a heal: with a `client_token` only that task is cancelled and its
+    /// final status returned; without one, every heal task at the path is
+    /// cancelled (the server answers with a start-success-shaped receipt).
+    pub async fn heal_stop(
+        &self,
+        bucket: Option<&str>,
+        prefix: Option<&str>,
+        client_token: Option<&str>,
+    ) -> Result<HealStopOutcome, AdminClientError> {
+        let mut query = vec![("forceStop", "true".to_string())];
+        if let Some(token) = client_token {
+            query.push(("clientToken", token.to_string()));
+        }
+        match client_token {
+            Some(_) => {
+                let status: HealTaskStatus = self.post_json(&heal_path(bucket, prefix), &query, Vec::new()).await?;
+                Ok(HealStopOutcome::Stopped(status))
+            }
+            None => {
+                let success: HealStartSuccess = self.post_json(&heal_path(bucket, prefix), &query, Vec::new()).await?;
+                Ok(HealStopOutcome::PathStopped(success))
+            }
+        }
+    }
+
+    /// Cluster-aggregated background heal status.
+    pub async fn background_heal_status(&self) -> Result<BackgroundHealStatus, AdminClientError> {
+        self.get_json("/v3/background-heal/status").await
+    }
+
+    /// Data scanner status (enabled state, freshness, runtime config).
+    pub async fn scanner_status(&self) -> Result<ScannerStatus, AdminClientError> {
+        self.get_json("/v3/scanner/status").await
+    }
+
+    /// ILM expiry worker status. The payload is owned by the expiry
+    /// subsystem and still evolving; returned verbatim.
+    pub async fn ilm_expiry_status(&self) -> Result<serde_json::Value, AdminClientError> {
+        self.get_json("/v3/ilm/expiry/status").await
+    }
+
+    /// Durable replacement-recovery status (admin v4). The payload is owned
+    /// by the heal runtime; returned verbatim.
+    pub async fn replacement_recovery_status(&self) -> Result<serde_json::Value, AdminClientError> {
+        self.get_json("/v4/heal/replacement-recovery").await
+    }
+
+    /// Signed GET returning a decoded JSON body; escape hatch for endpoints
+    /// this client does not wrap yet.
+    pub async fn get_json<T: for<'de> Deserialize<'de>>(&self, path: &str) -> Result<T, AdminClientError> {
+        let url = self.url_for(path, &[])?;
+        let request = self.sign_and_build(Method::GET, url, Vec::new(), None).await?;
+        self.execute(request).await
+    }
+
+    /// Signed POST returning a decoded JSON body.
+    async fn post_json<T: for<'de> Deserialize<'de>>(
+        &self,
+        path: &str,
+        query: &[(&str, String)],
+        body: Vec<u8>,
+    ) -> Result<T, AdminClientError> {
+        let content_type = if body.is_empty() { None } else { Some("application/json") };
+        let url = self.url_for(path, query)?;
+        let request = self.sign_and_build(Method::POST, url, body, content_type).await?;
+        self.execute(request).await
+    }
+
+    fn url_for(&self, path: &str, query: &[(&str, String)]) -> Result<reqwest::Url, AdminClientError> {
+        let mut url = self
+            .endpoint
+            .join(&format!("{}{}", self.api_prefix.trim_end_matches('/'), path))
+            .map_err(|err| AdminClientError::InvalidEndpoint(err.to_string()))?;
+        if !query.is_empty() {
+            let mut pairs = url.query_pairs_mut();
+            for (key, value) in query {
+                pairs.append_pair(key, value);
+            }
+        }
+        Ok(url)
+    }
+
+    /// Build a SigV4-signed request via the same signer the server trusts,
+    /// then hand the signed headers to the HTTP client. The signature covers
+    /// method, path, query, and an unsigned-payload marker — the same shape
+    /// RustFS itself sends for peer admin calls.
+    async fn sign_and_build(
+        &self,
+        method: Method,
+        url: reqwest::Url,
+        body: Vec<u8>,
+        content_type: Option<&str>,
+    ) -> Result<reqwest::Request, AdminClientError> {
+        let authority = match (url.host_str(), url.port_or_known_default()) {
+            (Some(host), Some(port)) => format!("{host}:{port}"),
+            _ => return Err(AdminClientError::InvalidEndpoint("endpoint has no authority".to_string())),
+        };
+        let mut builder = http::Request::builder()
+            .method(method.clone())
+            .uri(url.as_str())
+            .header(http::header::HOST, &authority)
+            .header("x-amz-content-sha256", rustfs_signer::constants::UNSIGNED_PAYLOAD);
+        if let Some(content_type) = content_type {
+            builder = builder.header(http::header::CONTENT_TYPE, content_type);
+        }
+        let unsigned = builder
+            .body(s3s::Body::empty())
+            .map_err(|err| AdminClientError::InvalidEndpoint(format!("build request failed: {err}")))?;
+        let signed = rustfs_signer::sign_v4(
+            unsigned,
+            body.len() as i64,
+            &self.access_key,
+            &self.secret_key,
+            &self.session_token,
+            &self.region,
+        );
+
+        let mut request = self
+            .http
+            .request(method, url)
+            .body(body)
+            .build()
+            .map_err(AdminClientError::Transport)?;
+        let headers = request.headers_mut();
+        for (name, value) in signed.headers().iter() {
+            // HOST is owned by the HTTP client; the signed value above was
+            // built from the same URL authority, so they always agree.
+            if name == http::header::HOST {
+                continue;
+            }
+            headers.insert(name, value.clone());
+        }
+        Ok(request)
+    }
+
+    async fn execute<T: for<'de> Deserialize<'de>>(&self, request: reqwest::Request) -> Result<T, AdminClientError> {
+        let response = self.http.execute(request).await?;
+        let status = response.status();
+        let bytes = response.bytes().await?;
+        if !status.is_success() {
+            return Err(AdminClientError::HttpStatus {
+                status: status.as_u16(),
+                body: String::from_utf8_lossy(&bytes).into_owned(),
+            });
+        }
+        serde_json::from_slice(&bytes).map_err(|err| AdminClientError::Decode {
+            message: err.to_string(),
+        })
+    }
+}
+
+/// Response of [`AdminClient::heal_stop`]: cancelling a single tokened task
+/// answers with that task's status, cancelling a whole path answers with a
+/// start-success-shaped receipt.
+#[derive(Debug, Clone)]
+pub enum HealStopOutcome {
+    Stopped(HealTaskStatus),
+    PathStopped(HealStartSuccess),
+}
+
+fn heal_path(bucket: Option<&str>, prefix: Option<&str>) -> String {
+    match (bucket, prefix) {
+        (Some(bucket), Some(prefix)) if !bucket.is_empty() && !prefix.is_empty() => {
+            format!("/v3/heal/{}/{}", percent_encode_path_segment(bucket), percent_encode_path_segment(prefix))
+        }
+        (Some(bucket), Some(_)) | (Some(bucket), None) if !bucket.is_empty() => {
+            format!("/v3/heal/{}", percent_encode_path_segment(bucket))
+        }
+        _ => "/v3/heal/".to_string(),
+    }
+}
+
+/// Encode a single path segment (slashes are content, not separators, inside
+/// bucket/prefix path params).
+fn percent_encode_path_segment(segment: &str) -> String {
+    let mut out = String::with_capacity(segment.len());
+    for byte in segment.bytes() {
+        match byte {
+            b'A'..=b'Z' | b'a'..=b'z' | b'0'..=b'9' | b'-' | b'_' | b'.' | b'~' => out.push(byte as char),
+            _ => out.push_str(&format!("%{byte:02X}")),
+        }
+    }
+    out
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{
+        AdminClient, AdminClientError, BackgroundHealStatus, HealOpts, HealScanMode, HealStartSuccess, HealTaskStatus,
+        ScannerStatus, heal_path, percent_encode_path_segment,
+    };
+    use serde_json::json;
+    use std::sync::{Arc, Mutex};
+
+    #[test]
+    fn heal_paths_cover_root_bucket_and_prefix() {
+        assert_eq!(heal_path(None, None), "/v3/heal/");
+        assert_eq!(heal_path(Some(""), Some("")), "/v3/heal/");
+        assert_eq!(heal_path(Some("bucket"), None), "/v3/heal/bucket");
+        assert_eq!(heal_path(Some("bucket"), Some("pre/fix")), "/v3/heal/bucket/pre%2Ffix");
+    }
+
+    #[test]
+    fn path_segments_percent_encode_reserved_characters() {
+        assert_eq!(percent_encode_path_segment("a b"), "a%20b");
+        assert_eq!(percent_encode_path_segment("a/b"), "a%2Fb");
+        assert_eq!(percent_encode_path_segment("ü"), "%C3%BC");
+    }
+
+    #[test]
+    fn heal_opts_round_trip_through_the_server_wire_shape() {
+        let opts = HealOpts {
+            recursive: true,
+            dry_run: false,
+            remove: true,
+            recreate: false,
+            scan_mode: HealScanMode::Deep,
+            update_parity: true,
+            no_lock: false,
+            pool: Some(1),
+            set: Some(2),
+        };
+        let wire = serde_json::to_value(&opts).unwrap();
+        assert_eq!(wire["scanMode"], json!(2), "the server body decodes scanMode as a number");
+        let back: HealOpts = serde_json::from_value(wire).unwrap();
+        assert_eq!(back.scan_mode, HealScanMode::Deep);
+        assert_eq!(back.pool, Some(1));
+    }
+
+    #[test]
+    fn heal_scan_mode_accepts_both_wire_encodings() {
+        assert_eq!(serde_json::from_value::<HealScanMode>(json!(1)).unwrap(), HealScanMode::Normal);
+        assert_eq!(serde_json::from_value::<HealScanMode>(json!("deep")).unwrap(), HealScanMode::Deep);
+        assert!(serde_json::from_value::<HealScanMode>(json!(9)).is_err());
+        assert!(serde_json::from_value::<HealScanMode>(json!("sideways")).is_err());
+    }
+
+    #[test]
+    fn heal_task_status_decodes_the_server_response_shape() {
+        let raw = json!({
+            "summary": "finished",
+            "detail": "",
+            "startTime": "2026-08-17T00:00:00Z",
+            "settings": {"recursive": false, "scanMode": 1},
+            "items": [{
+                "resultId": 1, "type": "object", "bucket": "b", "object": "o", "versionId": "", "detail": "",
+                "parityBlocks": 2, "dataBlocks": 2, "diskCount": 4, "setCount": 1,
+                "before": {"drives": []}, "after": {"drives": []}, "objectSize": 128
+            }],
+            "truncated": false
+        });
+        let status: HealTaskStatus = serde_json::from_value(raw).unwrap();
+        assert_eq!(status.summary, "finished");
+        assert_eq!(status.items.len(), 1);
+        assert_eq!(status.settings.scan_mode, HealScanMode::Normal);
+        assert!(status.progress.is_none());
+    }
+
+    #[test]
+    fn background_heal_status_types_known_fields_and_passes_the_rest_through() {
+        let raw = json!({
+            "state": "active",
+            "bitrotStartTime": "t",
+            "healQueueLength": 3,
+            "healActiveTasks": 1,
+            "healOperations": {"queueLength": 3},
+            "clusterStatusComplete": true
+        });
+        let status: BackgroundHealStatus = serde_json::from_value(raw).unwrap();
+        assert_eq!(status.state, "active");
+        assert_eq!(status.heal_queue_length, 3);
+        assert!(status.cluster_status_complete);
+        assert!(status.extra.contains_key("healOperations"), "unknown nested payloads must pass through");
+    }
+
+    #[test]
+    fn scanner_status_defaults_freshness_to_unknown() {
+        let raw = json!({"enabled": true, "freshness": {"state": "stale"}, "metrics": {}});
+        let status: ScannerStatus = serde_json::from_value(raw).unwrap();
+        assert_eq!(status.freshness(), "stale");
+        let bare: ScannerStatus = serde_json::from_value(json!({"enabled": false})).unwrap();
+        assert_eq!(bare.freshness(), "unknown");
+    }
+
+    #[test]
+    fn invalid_endpoint_is_rejected_without_io() {
+        let err = AdminClient::new("not a url", "ak", "sk").unwrap_err();
+        assert!(matches!(err, AdminClientError::InvalidEndpoint(_)));
+    }
+
+    #[tokio::test]
+    async fn signed_requests_carry_sigv4_authorization_and_correct_target() {
+        let server = TestServer::spawn(r#"{"clientToken":"token-1","clientAddress":"127.0.0.1:9","startTime":"t"}"#, 200).await;
+        let client = AdminClient::new(&format!("http://{}", server.addr), "minioadmin", "minioadmin")
+            .expect("client builds against the test server");
+
+        let start: HealStartSuccess = client
+            .heal_start(
+                Some("bucket"),
+                None,
+                &HealOpts {
+                    recursive: true,
+                    ..Default::default()
+                },
+                false,
+            )
+            .await
+            .expect("signed heal start decodes");
+
+        assert_eq!(start.client_token, "token-1");
+        let request = server.recorded();
+        assert_eq!(request.method, "POST");
+        assert_eq!(request.path, "/rustfs/admin/v3/heal/bucket");
+        assert!(!request.query.contains("forceStart"), "absent flags must not be sent");
+        let auth = request.header("authorization").expect("request must be signed");
+        assert!(auth.starts_with("AWS4-HMAC-SHA256"), "SigV4 scheme, got: {auth}");
+        assert!(auth.contains("Credential=minioadmin/"), "credentials must be in the Authorization header");
+        assert_eq!(
+            request.header("x-amz-content-sha256").as_deref(),
+            Some("UNSIGNED-PAYLOAD"),
+            "the client signs the same payload marker RustFS peer calls use"
+        );
+        assert_eq!(request.header("content-type").as_deref(), Some("application/json"));
+        assert!(request.body.contains("\"recursive\":true"));
+    }
+
+    #[tokio::test]
+    async fn query_sends_client_token_on_the_same_path() {
+        let body = r#"{"summary":"running","detail":"","settings":{"recursive":false},"items":[],"truncated":false}"#;
+        let server = TestServer::spawn(body, 200).await;
+        let client = AdminClient::new(&format!("http://{}", server.addr), "ak", "sk").unwrap();
+
+        let status = client
+            .heal_status(Some("bucket"), None, "token-1")
+            .await
+            .expect("status decodes");
+        assert_eq!(status.summary, "running");
+        let request = server.recorded();
+        assert_eq!(request.path, "/rustfs/admin/v3/heal/bucket");
+        assert!(request.query.contains("clientToken=token-1"));
+        assert!(!request.query.contains("forceStop"));
+    }
+
+    #[tokio::test]
+    async fn stop_without_token_takes_the_path_cancel_branch() {
+        let server = TestServer::spawn(r#"{"clientToken":"path","clientAddress":"c","startTime":"t"}"#, 200).await;
+        let client = AdminClient::new(&format!("http://{}", server.addr), "ak", "sk").unwrap();
+
+        let outcome = client.heal_stop(Some("bucket"), None, None).await.expect("path stop decodes");
+        assert!(matches!(outcome, super::HealStopOutcome::PathStopped(_)));
+        let request = server.recorded();
+        assert!(request.query.contains("forceStop=true"));
+        assert!(!request.query.contains("clientToken"));
+    }
+
+    #[tokio::test]
+    async fn http_error_status_maps_to_a_typed_error_with_body() {
+        let server = TestServer::spawn(r#"{"code":"AccessDenied","message":"denied"}"#, 403).await;
+        let client = AdminClient::new(&format!("http://{}", server.addr), "ak", "sk").unwrap();
+        let err = client.scanner_status().await.unwrap_err();
+        match err {
+            AdminClientError::HttpStatus { status, body } => {
+                assert_eq!(status, 403);
+                assert!(body.contains("AccessDenied"));
+            }
+            other => panic!("expected HttpStatus, got {other:?}"),
+        }
+    }
+
+    #[tokio::test]
+    async fn malformed_success_body_maps_to_a_decode_error() {
+        let server = TestServer::spawn("not json", 200).await;
+        let client = AdminClient::new(&format!("http://{}", server.addr), "ak", "sk").unwrap();
+        assert!(matches!(client.scanner_status().await.unwrap_err(), AdminClientError::Decode { .. }));
+    }
+
+    /// One recorded request, parsed off the wire with the minimum needed for
+    /// assertions: method, path, query, headers, body.
+    #[derive(Debug, Clone)]
+    struct RecordedRequest {
+        method: String,
+        path: String,
+        query: String,
+        headers: Vec<(String, String)>,
+        body: String,
+    }
+
+    impl RecordedRequest {
+        fn header(&self, name: &str) -> Option<String> {
+            self.headers
+                .iter()
+                .find(|(key, _)| key.eq_ignore_ascii_case(name))
+                .map(|(_, value)| value.clone())
+        }
+    }
+
+    /// Minimal HTTP/1.1 server: one canned response per connection, every
+    /// request recorded behind an `Arc<Mutex>`. Deliberately dependency-free —
+    /// the assertions only need the raw request bytes.
+    struct TestServer {
+        addr: std::net::SocketAddr,
+        requests: Arc<Mutex<Vec<RecordedRequest>>>,
+    }
+
+    impl TestServer {
+        async fn spawn(response_body: &'static str, status: u16) -> Self {
+            use tokio::io::{AsyncReadExt, AsyncWriteExt};
+
+            let listener = tokio::net::TcpListener::bind("127.0.0.1:0")
+                .await
+                .expect("bind ephemeral port");
+            let addr = listener.local_addr().expect("local addr");
+            let requests: Arc<Mutex<Vec<RecordedRequest>>> = Arc::new(Mutex::new(Vec::new()));
+
+            let recorded = requests.clone();
+            tokio::spawn(async move {
+                let reason = if status == 200 { "OK" } else { "Forbidden" };
+                let response = format!(
+                    "HTTP/1.1 {status} {reason}\r\ncontent-type: application/json\r\ncontent-length: {}\r\nconnection: close\r\n\r\n{response_body}",
+                    response_body.len()
+                );
+                // Each request is a fresh connection (connection: close); a
+                // bounded loop serves every call a test makes while letting
+                // the task exit instead of lingering for the whole process.
+                for _ in 0..16 {
+                    let Ok((mut stream, _)) = listener.accept().await else {
+                        break;
+                    };
+                    let mut buffer = Vec::with_capacity(2048);
+                    let mut chunk = [0u8; 2048];
+                    // Read headers plus content-length body, or stop on close.
+                    loop {
+                        if let Some(end) = find_header_end(&buffer) {
+                            let content_length = extract_content_length(&buffer[..end]);
+                            if buffer.len() >= end + content_length {
+                                break;
+                            }
+                        }
+                        let n = match stream.read(&mut chunk).await {
+                            Ok(0) | Err(_) => break,
+                            Ok(n) => n,
+                        };
+                        buffer.extend_from_slice(&chunk[..n]);
+                        if buffer.len() > 64 * 1024 {
+                            break;
+                        }
+                    }
+                    if let Some(request) = parse_request(&buffer) {
+                        recorded.lock().expect("recorded lock").push(request);
+                    }
+                    let _ = stream.write_all(response.as_bytes()).await;
+                    let _ = stream.shutdown().await;
+                }
+            });
+
+            Self { addr, requests }
+        }
+
+        fn recorded(&self) -> RecordedRequest {
+            self.requests
+                .lock()
+                .expect("recorded lock")
+                .last()
+                .cloned()
+                .expect("the client call must have produced one recorded request")
+        }
+    }
+
+    fn find_header_end(buffer: &[u8]) -> Option<usize> {
+        buffer.windows(4).position(|window| window == b"\r\n\r\n").map(|pos| pos + 4)
+    }
+
+    fn extract_content_length(headers: &[u8]) -> usize {
+        let text = String::from_utf8_lossy(headers).to_ascii_lowercase();
+        text.lines()
+            .find_map(|line| line.strip_prefix("content-length:"))
+            .and_then(|value| value.trim().parse().ok())
+            .unwrap_or(0)
+    }
+
+    fn parse_request(raw: &[u8]) -> Option<RecordedRequest> {
+        let end = find_header_end(raw)?;
+        let head = String::from_utf8_lossy(&raw[..end]);
+        let body = String::from_utf8_lossy(&raw[end..]).into_owned();
+        let mut lines = head.lines();
+        let request_line = lines.next()?;
+        let mut parts = request_line.split_whitespace();
+        let method = parts.next()?.to_string();
+        let target = parts.next()?.to_string();
+        let (path, query) = match target.split_once('?') {
+            Some((path, query)) => (path.to_string(), query.to_string()),
+            None => (target, String::new()),
+        };
+        let headers = lines
+            .filter_map(|line| line.split_once(':'))
+            .map(|(name, value)| (name.trim().to_string(), value.trim().to_string()))
+            .collect();
+        Some(RecordedRequest {
+            method,
+            path,
+            query,
+            headers,
+            body,
+        })
+    }
+}

crates/madmin/src/lib.rs

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+pub mod client;
 pub mod group;
 pub mod heal_commands;
 pub mod health;
@@ -25,6 +26,7 @@ pub mod trace;
 pub mod user;
 pub mod utils;
 
+pub use client::*;
 pub use group::*;
 pub use info_commands::*;
 pub use policy::*;

crates/scanner/Cargo.toml

@@ -108,6 +108,9 @@ temp-env = { workspace = true }
 tempfile = { workspace = true }
 uuid = { workspace = true, features = ["v4", "serde", "fast-rng", "macro-diagnostics"] }
 tokio = { workspace = true, features = ["test-util", "fs", "rt-multi-thread"] }
+# Test-only: pins the emitted scanner alert wire names against the canonical
+# EventName string forms subscribers configure (rustfs/backlog#1868).
+rustfs-s3-types.workspace = true
 # Enables the shared MockWarmBackend / xl.meta assertion helpers exposed via
 # the ecstore `api::tier::test_util` facade module (rustfs/backlog#1148 ilm-6).
 rustfs-ecstore = { workspace = true, features = ["test-util"] }

crates/scanner/src/scanner_folder.rs

@@ -12,10 +12,10 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use std::collections::HashSet;
+use std::collections::{HashMap, HashSet};
 use std::fs::FileType;
 use std::io::ErrorKind;
-use std::sync::{Arc, Once};
+use std::sync::{Arc, Mutex, Once};
 use std::time::{Duration, Instant, SystemTime};
 
 use crate::ReplTargetSizeSummary;
@@ -32,6 +32,7 @@ use crate::scanner_io::{
     SCANNER_SKIP_FILE_ERROR, ScannerIODisk as _, is_scanner_metadata_corrupt_error, is_scanner_metadata_transient_error,
 };
 use crate::sleeper::DynamicSleeper;
+use crate::storage_api::owner::{EcstoreEventArgs, ecstore_send_event};
 use metrics::{counter, describe_counter};
 use rustfs_common::heal_channel::{
     HEAL_DELETE_DANGLING, HealAdmissionDropReason, HealAdmissionResult, HealChannelPriority, HealChannelRequest,
@@ -97,6 +98,101 @@ const METRIC_SCANNER_EXCESS_FOLDERS_TOTAL: &str = "rustfs_scanner_excess_folders
 const METRIC_SCANNER_PENDING_HEAL_PRUNE_TOTAL: &str = "rustfs_scanner_pending_heal_prune_total";
 const METRIC_SCANNER_PENDING_HEAL_MALFORMED_TOTAL: &str = "rustfs_scanner_pending_heal_malformed_total";
 const MAX_PENDING_SCANNER_HEAL_RETRIES_PER_BUCKET: usize = 128;
+
+// --- scanner excess alerts as S3 notification events (rustfs/backlog#1868) --
+//
+// The excess-versions / excess-version-size / excess-folders alerts were
+// metrics-and-logs only; subscribers (consoles, external auditors) had no way
+// to hear them. MinIO emits s3:ObjectManyVersions / s3:ObjectLargeVersions /
+// s3:PrefixManyFolders for the same conditions — RustFS carries those as
+// EventName::Scanner* with the wire names below. Without a cooldown a single
+// over-threshold object would re-emit on every scan cycle (~a minute), so
+// emissions are edge-held per (kind, bucket, object) for 24h.
+
+/// `s3:Scanner:ManyVersions` (MinIO `s3:ObjectManyVersions`).
+pub const EVENT_SCANNER_MANY_VERSIONS: &str = "s3:Scanner:ManyVersions";
+/// `s3:Scanner:LargeVersions` (MinIO `s3:ObjectLargeVersions`).
+pub const EVENT_SCANNER_LARGE_VERSIONS: &str = "s3:Scanner:LargeVersions";
+/// `s3:Scanner:BigPrefix` (MinIO `s3:PrefixManyFolders`).
+pub const EVENT_SCANNER_BIG_PREFIX: &str = "s3:Scanner:BigPrefix";
+const ENV_SCANNER_ALERT_COOLDOWN_SECS: &str = "RUSTFS_SCANNER_ALERT_COOLDOWN_SECS";
+const DEFAULT_SCANNER_ALERT_COOLDOWN_SECS: u64 = 86_400;
+/// Hard cap on distinct cooldown keys; a pathological number of over-threshold
+/// objects clears the map wholesale instead of growing without bound (the
+/// worst case is one re-emission per still-hot key per scan cycle).
+const MAX_SCANNER_ALERT_COOLDOWN_KEYS: usize = 4096;
+
+/// Distinct alert kinds sharing one cooldown map.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+enum ScannerAlertKind {
+    ManyVersions,
+    LargeVersions,
+    BigPrefix,
+}
+
+type ScannerAlertCooldownKey = (ScannerAlertKind, String, String);
+type ScannerAlertCooldownMap = HashMap<ScannerAlertCooldownKey, Instant>;
+
+static SCANNER_ALERT_EMISSION_COOLDOWN: Mutex<Option<ScannerAlertCooldownMap>> = Mutex::new(None);
+
+fn scanner_alert_cooldown() -> Duration {
+    let raw = std::env::var(ENV_SCANNER_ALERT_COOLDOWN_SECS)
+        .ok()
+        .and_then(|v| v.parse::<u64>().ok());
+    Duration::from_secs(raw.unwrap_or(DEFAULT_SCANNER_ALERT_COOLDOWN_SECS))
+}
+
+/// Edge-held emission gate: returns `true` (and records the cooldown) only
+/// when this (kind, bucket, object) last fired longer than the cooldown ago —
+/// or never. Metrics and logs stay level-triggered every cycle; only the
+/// notification events are held back.
+fn scanner_alert_emission_allows(kind: ScannerAlertKind, bucket: &str, object: &str, cooldown: Duration) -> bool {
+    let key = (kind, bucket.to_string(), object.to_string());
+    let mut guard = SCANNER_ALERT_EMISSION_COOLDOWN
+        .lock()
+        .unwrap_or_else(|poison| poison.into_inner());
+    let guard = guard.get_or_insert_with(ScannerAlertCooldownMap::new);
+    let now = Instant::now();
+    // Expired entries leave first; the cap is still exceeded only when live
+    // keys alone overflow it, in which case a wholesale clear trades one
+    // extra emission per hot key for a hard memory bound.
+    if guard.len() >= MAX_SCANNER_ALERT_COOLDOWN_KEYS {
+        guard.retain(|_, fired_at| now.duration_since(*fired_at) < cooldown);
+        if guard.len() >= MAX_SCANNER_ALERT_COOLDOWN_KEYS {
+            guard.clear();
+        }
+    }
+    match guard.get(&key) {
+        Some(fired_at) if now.duration_since(*fired_at) < cooldown => false,
+        _ => {
+            guard.insert(key, now);
+            true
+        }
+    }
+}
+
+/// Emit a scanner alert as an S3 notification event through the standard
+/// dispatch pipeline. Fire-and-forget: the notify layer owns delivery,
+/// retry, and target filtering; the scanner never waits on it.
+fn emit_scanner_alert_event(event_name: &str, bucket: &str, object: &str, size: i64, details: &[(&str, String)]) {
+    let mut req_params = HashMap::with_capacity(details.len());
+    for (key, value) in details {
+        req_params.insert((*key).to_string(), value.clone());
+    }
+    ecstore_send_event(EcstoreEventArgs {
+        event_name: event_name.to_string(),
+        bucket_name: bucket.to_string(),
+        object: crate::ScannerObjectInfo {
+            bucket: bucket.to_string(),
+            name: object.to_string(),
+            size,
+            ..Default::default()
+        },
+        req_params,
+        user_agent: "Scanner".to_string(),
+        ..Default::default()
+    });
+}
 const MAX_PENDING_SCANNER_HEALS_PER_BUCKET: usize = 10_000;
 
 static SCANNER_INLINE_HEAL_WARN_ONCE: Once = Once::new();
@@ -1197,6 +1293,7 @@ impl ScannerItem {
     fn alert_excessive_versions(&self, remaining_versions: usize, cumulative_size: i64) {
         ensure_scanner_alert_metrics_registered();
         let (too_many_versions, too_large_versions) = should_alert_excessive_versions(remaining_versions, cumulative_size);
+        let object_path = self.object_path();
         if too_many_versions {
             global_metrics().record_scanner_source_executed(ScannerWorkSource::Alerts, 1);
             counter!(
@@ -1204,13 +1301,26 @@ impl ScannerItem {
                 "bucket" => self.bucket.clone()
             )
             .increment(1);
+            if scanner_alert_emission_allows(ScannerAlertKind::ManyVersions, &self.bucket, &object_path, scanner_alert_cooldown())
+            {
+                emit_scanner_alert_event(
+                    EVENT_SCANNER_MANY_VERSIONS,
+                    &self.bucket,
+                    &object_path,
+                    cumulative_size,
+                    &[
+                        ("versions", remaining_versions.to_string()),
+                        ("threshold", scanner_excess_versions_threshold().to_string()),
+                    ],
+                );
+            }
             warn!(
                 target: "rustfs::scanner::folder",
                 event = EVENT_SCANNER_ALERT_STATE,
                 component = LOG_COMPONENT_SCANNER,
                 subsystem = LOG_SUBSYSTEM_FOLDER,
                 bucket = %self.bucket,
-                object = %self.object_path(),
+                object = %object_path,
                 versions = remaining_versions,
                 threshold = scanner_excess_versions_threshold(),
                 state = "excess_versions",
@@ -1224,13 +1334,31 @@ impl ScannerItem {
                 "bucket" => self.bucket.clone()
             )
             .increment(1);
+            if scanner_alert_emission_allows(
+                ScannerAlertKind::LargeVersions,
+                &self.bucket,
+                &object_path,
+                scanner_alert_cooldown(),
+            ) {
+                emit_scanner_alert_event(
+                    EVENT_SCANNER_LARGE_VERSIONS,
+                    &self.bucket,
+                    &object_path,
+                    cumulative_size,
+                    &[
+                        ("versions", remaining_versions.to_string()),
+                        ("cumulativeSize", cumulative_size.to_string()),
+                        ("threshold", scanner_excess_version_size_threshold().to_string()),
+                    ],
+                );
+            }
             warn!(
                 target: "rustfs::scanner::folder",
                 event = EVENT_SCANNER_ALERT_STATE,
                 component = LOG_COMPONENT_SCANNER,
                 subsystem = LOG_SUBSYSTEM_FOLDER,
                 bucket = %self.bucket,
-                object = %self.object_path(),
+                object = %object_path,
                 versions = remaining_versions,
                 cumulative_size,
                 threshold = scanner_excess_version_size_threshold(),
@@ -1611,6 +1739,15 @@ impl FolderScanner {
             "root" => self.root.clone()
         )
         .increment(1);
+        if scanner_alert_emission_allows(ScannerAlertKind::BigPrefix, &self.root, folder, scanner_alert_cooldown()) {
+            emit_scanner_alert_event(
+                EVENT_SCANNER_BIG_PREFIX,
+                &self.root,
+                folder,
+                0,
+                &[("folders", total_folders.to_string()), ("threshold", threshold.to_string())],
+            );
+        }
         warn!(
             target: "rustfs::scanner::folder",
             event = EVENT_SCANNER_ALERT_STATE,
@@ -3076,6 +3213,90 @@ mod tests {
     #[cfg(unix)]
     use std::os::unix::fs::{PermissionsExt, symlink};
     use std::sync::Mutex;
+
+    /// Reset the process-global alert cooldown map; test-only.
+    fn reset_alert_cooldowns() {
+        *SCANNER_ALERT_EMISSION_COOLDOWN
+            .lock()
+            .unwrap_or_else(|poison| poison.into_inner()) = Some(ScannerAlertCooldownMap::new());
+    }
+
+    /// The emitted event-name strings must be exactly what `EventName`
+    /// serializes, or a bucket notification subscribed to the documented name
+    /// would silently never match (rustfs/backlog#1868).
+    #[test]
+    fn scanner_alert_wire_names_match_canonical_event_names() {
+        use rustfs_s3_types::EventName;
+        assert_eq!(EVENT_SCANNER_MANY_VERSIONS, EventName::ScannerManyVersions.to_string());
+        assert_eq!(EVENT_SCANNER_LARGE_VERSIONS, EventName::ScannerLargeVersions.to_string());
+        assert_eq!(EVENT_SCANNER_BIG_PREFIX, EventName::ScannerBigPrefix.to_string());
+    }
+
+    fn cooldown_map_len() -> usize {
+        SCANNER_ALERT_EMISSION_COOLDOWN
+            .lock()
+            .unwrap_or_else(|poison| poison.into_inner())
+            .as_ref()
+            .map(|map| map.len())
+            .unwrap_or(0)
+    }
+
+    /// Backdate every recorded cooldown so the next check fires again.
+    fn expire_all_alert_cooldowns(cooldown: Duration) {
+        let now = Instant::now();
+        let mut guard = SCANNER_ALERT_EMISSION_COOLDOWN
+            .lock()
+            .unwrap_or_else(|poison| poison.into_inner());
+        if let Some(map) = guard.as_mut() {
+            for fired_at in map.values_mut() {
+                if let Some(expired) = now.checked_sub(cooldown + Duration::from_secs(1)) {
+                    *fired_at = expired;
+                }
+            }
+        }
+    }
+
+    /// The emission gate is the only thing standing between an over-threshold
+    /// object and one S3 event per scan cycle, so its edge semantics get
+    /// pinned directly. All scenarios share one #[test] because the cooldown
+    /// map is process-global and parallel tests would read each other's
+    /// firings.
+    #[test]
+    fn scanner_alert_emission_is_edge_held_per_key_and_bounded() {
+        reset_alert_cooldowns();
+        let cooldown = Duration::from_secs(3600);
+
+        // First firing allows, an immediate re-check is held.
+        assert!(scanner_alert_emission_allows(ScannerAlertKind::ManyVersions, "bkt", "obj", cooldown));
+        assert!(!scanner_alert_emission_allows(ScannerAlertKind::ManyVersions, "bkt", "obj", cooldown));
+
+        // Different kind, object, and bucket are independent keys.
+        assert!(scanner_alert_emission_allows(ScannerAlertKind::LargeVersions, "bkt", "obj", cooldown));
+        assert!(scanner_alert_emission_allows(ScannerAlertKind::ManyVersions, "bkt", "other", cooldown));
+        assert!(scanner_alert_emission_allows(ScannerAlertKind::ManyVersions, "other", "obj", cooldown));
+        assert_eq!(cooldown_map_len(), 4);
+
+        // After the cooldown elapses the same key fires again.
+        expire_all_alert_cooldowns(cooldown);
+        assert!(scanner_alert_emission_allows(ScannerAlertKind::ManyVersions, "bkt", "obj", cooldown));
+
+        // A zero cooldown degenerates to always-emit (operators may want that).
+        assert!(scanner_alert_emission_allows(ScannerAlertKind::BigPrefix, "bkt", "dir", Duration::ZERO));
+        assert!(scanner_alert_emission_allows(ScannerAlertKind::BigPrefix, "bkt", "dir", Duration::ZERO));
+
+        // Hard bound: overflow the cap with zero-cooldown keys and confirm the
+        // map clears rather than growing past it.
+        reset_alert_cooldowns();
+        for index in 0..=(MAX_SCANNER_ALERT_COOLDOWN_KEYS + 8) {
+            let _ = scanner_alert_emission_allows(ScannerAlertKind::BigPrefix, "bkt", &format!("dir-{index}"), Duration::ZERO);
+        }
+        assert!(
+            cooldown_map_len() <= MAX_SCANNER_ALERT_COOLDOWN_KEYS,
+            "cooldown map must stay bounded, got {}",
+            cooldown_map_len()
+        );
+    }
+
     use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
     use temp_env::{with_var, with_var_unset};
     use tracing_subscriber::fmt::MakeWriter;

crates/scanner/src/storage_api.rs

@@ -78,6 +78,7 @@ pub(crate) use rustfs_ecstore::api::disk::{
 pub(crate) use rustfs_ecstore::api::error::{
     Error as EcstoreErrorType, Result as EcstoreResultType, StorageError as EcstoreStorageError,
 };
+pub(crate) use rustfs_ecstore::api::event::{EventArgs as EcstoreEventArgs, send_event as ecstore_send_event};
 #[cfg(test)]
 pub(crate) use rustfs_ecstore::api::layout::{
     EndpointServerPools as EcstoreEndpointServerPools, Endpoints as EcstoreEndpoints, PoolEndpoints as EcstorePoolEndpoints,
@@ -110,8 +111,8 @@ pub(crate) mod owner {
         ECSTORE_BUCKET_META_PREFIX, ECSTORE_RUSTFS_META_BUCKET, ECSTORE_STORAGE_FORMAT_FILE, ECSTORE_STORAGECLASS_RRS,
         ECSTORE_STORAGECLASS_STANDARD, ECSTORE_TRANSITION_COMPLETE, EcstoreBucketTargetSys, EcstoreBucketVersioningSys,
         EcstoreDisk, EcstoreDiskAPI, EcstoreDiskBytes, EcstoreDiskError, EcstoreDiskInfo, EcstoreDiskInfoOptions,
-        EcstoreDiskLocation, EcstoreDiskResult, EcstoreErrorType, EcstoreEvaluator, EcstoreEvent, EcstoreLcEventSrc,
-        EcstoreLifecycle, EcstoreListPathRawOptions, EcstoreNsScannerOpenRequest, EcstoreObjectOpts,
+        EcstoreDiskLocation, EcstoreDiskResult, EcstoreErrorType, EcstoreEvaluator, EcstoreEvent, EcstoreEventArgs,
+        EcstoreLcEventSrc, EcstoreLifecycle, EcstoreListPathRawOptions, EcstoreNsScannerOpenRequest, EcstoreObjectOpts,
         EcstoreReplicationConfigurationExt, EcstoreReplicationScannerBridge, EcstoreResultType, EcstoreScanGuard,
         EcstoreSetDisks, EcstoreStorageError, EcstoreStore, EcstoreTierConfig, EcstoreVersioningApi,
         ScannerReplicationHealObject, ScannerReplicationHealResult, ScannerReplicationQueueAdmission, ecstore_apply_expiry_rule,
@@ -121,7 +122,7 @@ pub(crate) mod owner {
         ecstore_is_erasure_sd, ecstore_is_reserved_or_invalid_bucket, ecstore_list_path_raw,
         ecstore_object_opts_from_object_info, ecstore_path2_bucket_object, ecstore_path2_bucket_object_with_base_path,
         ecstore_read_config, ecstore_replace_bucket_usage_memory_from_info, ecstore_resolve_object_store_handle,
-        ecstore_save_config, scanner_replication_config_for_lifecycle_eval,
+        ecstore_save_config, ecstore_send_event, scanner_replication_config_for_lifecycle_eval,
     };
 
     #[cfg(test)]

docs/operations/scanner-excess-alerts.md

@@ -0,0 +1,37 @@
+# Scanner Excess Alerts: Metrics, S3 Events, and Thresholds
+
+> 中文版：[scanner-excess-alerts_zh.md](scanner-excess-alerts_zh.md)
+
+Date: 2026-08-18 (rustfs/backlog#1868 / HS-04; includes the HS-15 threshold-delta notes)
+
+The background scanner detects three classes of "excess" conditions while it walks buckets and surfaces them as alerts. This page documents each alert's trigger condition, the subscribable S3 event, the cooldown semantics, and the threshold differences versus MinIO — for operators debugging alerts and for event consumers wiring up subscriptions.
+
+## The three alerts
+
+| Alert | Trigger (per scan cycle) | Metric | S3 event (RustFS wire name) | MinIO event name |
+|---|---|---|---|---|
+| Excess versions | Retained versions of one object ≥ `scanner:alert_excess_versions` | `rustfs_scanner_excess_object_versions_total{bucket}` | `s3:Scanner:ManyVersions` | `s3:ObjectManyVersions` |
+| Excess version size | Cumulative bytes of all versions of one object ≥ `scanner:alert_excess_version_size` | `rustfs_scanner_excess_object_version_size_total{bucket}` | `s3:Scanner:LargeVersions` | `s3:ObjectLargeVersions` |
+| Excess folders | Direct subfolders of one directory > `scanner:alert_excess_folders` | `rustfs_scanner_excess_folders_total{root}` | `s3:Scanner:BigPrefix` | `s3:PrefixManyFolders` |
+
+Subscribe like any bucket notification: configure a notification on the target bucket with the RustFS wire name above (or the `s3:Scanner:*` wildcard). Events carry `UserAgent: Scanner` as their origin marker, and `req_params` holds the observed value and the threshold (`versions` / `cumulativeSize` / `folders` / `threshold`), so consumers can judge severity directly.
+
+## Metrics and events fire on different cadences
+
+- **Metrics and structured logs are level-triggered**: as long as the object stays over the threshold, every scan cycle counts and logs it (default cycle ≈ 60s; see `scanner:speed`).
+- **S3 events are edge-triggered with a cooldown**: the same (alert kind, bucket, object) emits at most once per cooldown window — 24 hours by default (`RUSTFS_SCANNER_ALERT_COOLDOWN_SECS`; set it to 0 to emit every cycle). When the window lapses and the object is still over the threshold, the event fires again. The cooldown table lives in process memory with a 4096-entry hard cap; on overflow it is cleared and rebuilt (worst case: one extra emission per still-hot key).
+- A process restart resets the cooldown (every still-over-threshold object emits once more after a restart) — deliberately: restarts usually accompany incident response, and the re-emission buys visibility.
+
+## Threshold defaults and the MinIO deltas (HS-15)
+
+| Config key | ENV | RustFS default | MinIO default | Notes |
+|---|---|---|---|---|
+| `scanner:alert_excess_versions` | `RUSTFS_SCANNER_ALERT_EXCESS_VERSIONS` | 100 | 100 | Identical |
+| `scanner:alert_excess_version_size` | `RUSTFS_SCANNER_ALERT_EXCESS_VERSION_SIZE` | 1 TiB | 1 TB | Same order of magnitude; different unit basis (TiB vs TB) |
+| `scanner:alert_excess_folders` | `RUSTFS_SCANNER_ALERT_EXCESS_FOLDERS` | 65538 | 50000 | **Deliberate divergence**: 65538 tolerates the Proxmox Backup Server chunk layout (65536 chunks per directory plus the directory's own entries); MinIO's 50000 would fire continuously for PBS users. Set it to 50000 explicitly to match MinIO behavior |
+
+All three keys accept both env and admin config (`PUT /rustfs/admin/v3/config`, `scanner` subsystem); hot updates take effect immediately.
+
+## Why the event names are mapped
+
+RustFS's event enum (`rustfs_s3_types::EventName::ScannerManyVersions/LargeVersions/BigPrefix`) keeps the repo's established `s3:Scanner:*` wire names (literally different from MinIO's `s3:ObjectManyVersions`; the enum comments preserve the mapping). Subscribers should use the RustFS wire names in this page. If you need MinIO-literal compatibility, map the names on the console/consumer side — do not change the published wire names.

docs/operations/scanner-excess-alerts_zh.md

@@ -0,0 +1,37 @@
+# Scanner 超限告警：指标、S3 事件与阈值
+
+> English version: [scanner-excess-alerts.md](scanner-excess-alerts.md)
+
+日期：2026-08-18（rustfs/backlog#1868 / HS-04，含 HS-15 阈值差异说明）
+
+后台 scanner 在扫描过程中检测三类"超限"状态并对外告警。本文说明每类告警的触发条件、可订阅的 S3 事件、冷却语义，以及与 MinIO 的阈值差异，供运维排障与事件消费方对接。
+
+## 三类告警
+
+| 告警 | 触发条件（任一扫描周期） | 指标 | S3 事件（RustFS wire 名） | MinIO 对应事件名 |
+|---|---|---|---|---|
+| 版本数超限 | 单对象保留版本数 ≥ `scanner:alert_excess_versions` | `rustfs_scanner_excess_object_versions_total{bucket}` | `s3:Scanner:ManyVersions` | `s3:ObjectManyVersions` |
+| 版本总大小超限 | 单对象全部版本累计字节 ≥ `scanner:alert_excess_version_size` | `rustfs_scanner_excess_object_version_size_total{bucket}` | `s3:Scanner:LargeVersions` | `s3:ObjectLargeVersions` |
+| 子目录数超限 | 单目录直接子目录数 > `scanner:alert_excess_folders` | `rustfs_scanner_excess_folders_total{root}` | `s3:Scanner:BigPrefix` | `s3:PrefixManyFolders` |
+
+订阅方式与普通桶通知一致：对目标桶配置 notification，事件名填上表 RustFS wire 名（或通配 `s3:Scanner:*`）。事件以 `UserAgent: Scanner` 标记来源，`req_params` 携带实际值与阈值（`versions` / `cumulativeSize` / `folders` / `threshold`），便于消费方直接判断严重程度。
+
+## 指标与事件的触发节奏不同
+
+- **指标与结构化日志是电平触发**：只要对象仍在阈值之上，每个扫描周期都会计数/打日志（默认周期约 60s，见 `scanner:speed`）。
+- **S3 事件是边沿触发 + 冷却**：同一 (告警类型， 桶, 对象) 在冷却窗口内只发一次，默认 24 小时（`RUSTFS_SCANNER_ALERT_COOLDOWN_SECS`，设 0 表示每周期都发）。窗口过后对象仍超限会再次发出。冷却表在进程内有 4096 条硬顶，超限清空重建（最坏情况是每个仍超限的 key 多发一次）。
+- 进程重启会重置冷却（重启后每个仍超限的对象会再发一次）——这是有意为之：重启常伴随排障，重发提供可见性。
+
+## 阈值默认值与 MinIO 差异（HS-15）
+
+| 配置键 | ENV | RustFS 默认 | MinIO 默认 | 差异说明 |
+|---|---|---|---|---|
+| `scanner:alert_excess_versions` | `RUSTFS_SCANNER_ALERT_EXCESS_VERSIONS` | 100 | 100 | 一致 |
+| `scanner:alert_excess_version_size` | `RUSTFS_SCANNER_ALERT_EXCESS_VERSION_SIZE` | 1 TiB | 1 TB | 语义同量级，单位口径不同（TiB vs TB） |
+| `scanner:alert_excess_folders` | `RUSTFS_SCANNER_ALERT_EXCESS_FOLDERS` | 65538 | 50000 | **有意差异**：65538 兼容 Proxmox Backup Server 的 chunk 布局（每目录 65536 个 chunk + 目录自身条目），按 MinIO 的 50000 会对 PBS 用户持续误报。如需与 MinIO 行为一致可显式配置为 50000 |
+
+三个键均支持 env 与 admin config（`PUT /rustfs/admin/v3/config` 的 `scanner` 子系统）双通道，热更新即时生效。
+
+## 事件名映射的由来
+
+RustFS 的事件枚举（`rustfs_s3_types::EventName::ScannerManyVersions/LargeVersions/BigPrefix`）沿用仓库既有 wire 名 `s3:Scanner:*`（与 MinIO 的 `s3:ObjectManyVersions` 字面不同，枚举注释中保留了映射关系）。订阅方应以本文的 RustFS wire 名为准；如需 MinIO 字面兼容，请在 console/消费侧做名称映射，不要修改已发布的 wire 名。

rustfs/src/admin/handlers/site_replication.rs

@@ -6023,7 +6023,10 @@ fn edit_generation_wall_clock() -> u64 {
 /// node's clock behind the clock that fed the previous lifetime) mints
 /// below the stale mark and the origin stays fenced — but only until real
 /// time passes the previous lifetime's last allocation, because every later
-/// allocation takes the wall-clock floor again. Bounded by the skew,
+/// allocation takes the wall-clock floor again (and never longer than
+/// [`PEER_EDIT_FENCE_STALENESS_WINDOW_NANOS`]: a regression past the window
+/// leaves the mark implausibly distant and the origin runs unfenced
+/// immediately). Bounded by the skew,
 /// self-healing, and no rollback window beyond the plain counter's: a
 /// delivery applies only at or above the receiver's mark, so the one
 /// cross-lifetime interleaving that can apply stale content — a
@@ -6063,6 +6066,52 @@ fn peer_edit_fence(queries: &HashMap<String, String>) -> Option<(String, u64)> {
     Some((origin.clone(), generation))
 }
 
+/// How far below the recorded high-water mark a delivery may sit and still
+/// be fenced as stale. The distance a GENUINE superseded delivery can trail
+/// its origin's mark is small: retransmissions re-run the sender flow and
+/// mint a fresh generation (the retry queue keys on the bare path and never
+/// replays a fenced URL), so only an in-flight straggler of the losing
+/// fan-out race trails the mark, by delivery latency — minutes at the
+/// outside. A mark further above than this window cannot be explained by
+/// any genuine race, only by a forged fence (the shared service account
+/// lets any peer stamp any origin) or by a persisted clock excursion the
+/// origin has since left behind — and fencing on it would silently drop the
+/// origin's real edits, so the stale check ignores it instead.
+const PEER_EDIT_FENCE_STALENESS_WINDOW_NANOS: u64 = 24 * 60 * 60 * 1_000_000_000;
+
+/// Whether an incoming fence may be honoured, as far as this site can vouch
+/// for it. The sender's identity is unverifiable (shared service account),
+/// so the check runs over what the receiving state knows: the claimed origin
+/// must be a site this state currently replicates with — the same membership
+/// rule the load-time mark pruning applies, so every mark recorded behind
+/// this check is one a reload would keep — and not this site itself, which
+/// never delivers edits to itself. The caller IGNORES an inadmissible fence
+/// rather than failing the request: the delivery applies exactly as an
+/// unstamped (pre-fence) delivery would, no high-water mark is read or
+/// written, and the worst a forged fence achieves is forfeiting an ordering
+/// guarantee its sender was never owed. The generation itself is NOT
+/// bounded here: a genuine origin whose hybrid clock persisted a wall-clock
+/// excursion allocates arbitrarily far in the future, and refusing to
+/// record its marks would strip the ordering fence from exactly the
+/// deliveries that still race — the staleness window on the read side is
+/// what defuses forged marks instead.
+fn peer_edit_fence_is_admissible(state: &SiteReplicationState, local_deployment_id: &str, fence: &(String, u64)) -> bool {
+    let (origin, generation) = fence;
+    if origin != local_deployment_id && state.peers.contains_key(origin) {
+        return true;
+    }
+    warn!(
+        event = EVENT_ADMIN_SITE_REPLICATION_STATE,
+        component = LOG_COMPONENT_ADMIN,
+        subsystem = LOG_SUBSYSTEM_SITE_REPLICATION,
+        result = "fence_origin_not_a_remote_peer",
+        origin = %origin,
+        generation = *generation,
+        "ignoring inadmissible peer-edit fence"
+    );
+    false
+}
+
 /// True when a strictly newer edit from the same origin site already landed
 /// here. No lock on the sending side can order deliveries issued by two
 /// nodes of that site, so ordering is decided here, on the generation the
@@ -6070,11 +6119,42 @@ fn peer_edit_fence(queries: &HashMap<String, String>) -> Option<(String, u64)> {
 /// stale: one edit legitimately fans out several deliveries under a single
 /// generation (the ILM-expiry edit sends every peer's record), and a replay of
 /// an applied delivery re-applies the same edit idempotently.
+///
+/// A mark more than [`PEER_EDIT_FENCE_STALENESS_WINDOW_NANOS`] above the
+/// delivery is implausible and does NOT fence: the shared service account
+/// means any peer can stamp any origin, so a forged `u64::MAX`-scale mark
+/// would otherwise silently swallow the origin's genuine edits for good.
+/// Bounding the fence by distance instead of by an absolute ceiling keeps
+/// ordering intact wherever the origin's clock actually operates — two
+/// racing deliveries trail each other by seconds whether the hybrid clock
+/// tracks wall time or persists a long-gone excursion far ahead of it —
+/// while a mark no genuine race can explain merely downgrades the origin to
+/// unfenced (pre-fence) delivery instead of dropping its edits. (One genuine
+/// shape does land out here: a plain-counter straggler arriving after its
+/// origin's first hybrid-clock edit. It gets the same downgrade — applied
+/// unfenced — once, at upgrade time; fencing it instead would silence the
+/// mirror case, a hybrid-clock origin downgraded back to the plain counter.)
 fn peer_edit_delivery_is_stale(state: &SiteReplicationState, origin: &str, generation: u64) -> bool {
-    state
-        .applied_edit_generations
-        .get(origin)
-        .is_some_and(|applied| *applied > generation)
+    let Some(applied) = state.applied_edit_generations.get(origin) else {
+        return false;
+    };
+    if *applied <= generation {
+        return false;
+    }
+    if *applied - generation > PEER_EDIT_FENCE_STALENESS_WINDOW_NANOS {
+        warn!(
+            event = EVENT_ADMIN_SITE_REPLICATION_STATE,
+            component = LOG_COMPONENT_ADMIN,
+            subsystem = LOG_SUBSYSTEM_SITE_REPLICATION,
+            result = "fence_mark_beyond_staleness_window",
+            origin,
+            generation,
+            applied_mark = *applied,
+            "ignoring implausibly distant peer-edit high-water mark"
+        );
+        return false;
+    }
+    true
 }
 
 fn record_applied_peer_edit_generation(state: &mut SiteReplicationState, origin: &str, generation: u64) {
@@ -10698,6 +10778,11 @@ impl Operation for SRPeerEditHandler {
         let outcome = update_site_replication_state_when_changed(move |state| {
             let mut incoming = incoming;
             let local_peer = local_peer_at_endpoint(commit_endpoint, state);
+            // The fence is self-reported — the shared service account means
+            // the sender cannot be identified — so it is honoured only after
+            // the admissibility check, against the same state it will gate.
+            let commit_fence =
+                commit_fence.filter(|fence| peer_edit_fence_is_admissible(state, &local_peer.deployment_id, fence));
             // Ordering fence: the sending site allocates the generation under
             // its state-object lock, so a delivery that lost the race carries
             // a generation this site has already passed. Applying it would
@@ -13393,6 +13478,15 @@ mod tests {
             handler_block.contains("record_applied_peer_edit_generation(state, origin, *generation);"),
             "SRPeerEditHandler must record the applied generation so later stale deliveries are recognised"
         );
+        // Fence hardening: origin and generation are self-reported by a
+        // caller the shared service account cannot identify, so the handler
+        // must pass the fence through the admissibility check — against the
+        // same state the fence gates, i.e. inside the transaction — before
+        // reading or raising any high-water mark.
+        assert!(
+            handler_block.contains(".filter(|fence| peer_edit_fence_is_admissible(state, &local_peer.deployment_id, fence))"),
+            "SRPeerEditHandler must admit a fence only through peer_edit_fence_is_admissible inside the state transaction"
+        );
         // P1-15 PR2: both halves of the fence and the edit they fence share
         // ONE transaction. Checking the fence against a state read outside the
         // lock would let the check pass on one snapshot and the write land on
@@ -14769,6 +14863,121 @@ mod tests {
         assert!(peer_edit_delivery_is_stale(&state, origin, generation - 1));
     }
 
+    /// A fence is self-reported: every site authenticates peer traffic with
+    /// the same site-replicator credential, so a compromised peer can stamp
+    /// ANY origin with ANY generation. An origin the receiver does not
+    /// replicate with — or the receiver itself — is ignored and plants no
+    /// mark; a mark a compromised peer plants for a CURRENT origin cannot
+    /// silence that origin, because the staleness window refuses to fence on
+    /// a mark implausibly far above the genuine deliveries.
+    #[test]
+    fn forged_peer_edit_fences_cannot_poison_the_high_water_marks() {
+        let mut state = SiteReplicationState {
+            peers: BTreeMap::from([
+                (
+                    "site-local".to_string(),
+                    PeerInfo {
+                        deployment_id: "site-local".to_string(),
+                        ..peer("local", "https://local.example:9000")
+                    },
+                ),
+                (
+                    "site-victim".to_string(),
+                    PeerInfo {
+                        deployment_id: "site-victim".to_string(),
+                        ..peer("victim", "https://victim.example:9000")
+                    },
+                ),
+            ]),
+            ..Default::default()
+        };
+        // An origin outside the current membership is refused outright...
+        let unknown = ("site-unknown".to_string(), 4u64);
+        assert!(!peer_edit_fence_is_admissible(&state, "site-local", &unknown));
+
+        // No site delivers edits to itself: a fence claiming the receiver as
+        // its origin is forged by construction, current peer or not.
+        let own = ("site-local".to_string(), 4u64);
+        assert!(!peer_edit_fence_is_admissible(&state, "site-local", &own));
+
+        // A current remote peer's fence is admitted and works end to end.
+        let genuine = ("site-victim".to_string(), 1u64);
+        assert!(peer_edit_fence_is_admissible(&state, "site-local", &genuine));
+        assert!(!peer_edit_delivery_is_stale(&state, &genuine.0, genuine.1));
+        record_applied_peer_edit_generation(&mut state, &genuine.0, genuine.1);
+        assert_eq!(state.applied_edit_generations.get("site-victim"), Some(&1));
+
+        // A forged u64::MAX-scale mark CAN be recorded — the shared service
+        // account means the receiver cannot tell the stamp was forged — but
+        // it is inert: the victim's genuine hybrid-clock deliveries sit far
+        // more than the staleness window below it, so they keep applying
+        // instead of being silently acked-and-dropped.
+        record_applied_peer_edit_generation(&mut state, "site-victim", u64::MAX);
+        assert!(!peer_edit_delivery_is_stale(&state, "site-victim", edit_generation_wall_clock()));
+    }
+
+    /// The staleness window bounds the fence by DISTANCE from the mark, not
+    /// by an absolute clock ceiling, so ordering must hold wherever the
+    /// origin's hybrid clock actually operates. The regression that matters:
+    /// a temporary wall-clock excursion far in the future is persisted by
+    /// `next_peer_edit_generation` (`max(now, prev + 1)` never comes back
+    /// down), and two later edits g+1 then g can arrive in reverse order —
+    /// g must still be fenced, even though both generations dwarf the
+    /// receiver's clock. Conversely a mark further above a delivery than any
+    /// genuine race can explain must not fence it.
+    #[test]
+    fn peer_edit_fence_orders_a_persisted_future_clock_and_defuses_distant_marks() {
+        let mut state = SiteReplicationState {
+            peers: BTreeMap::from([(
+                "site-origin".to_string(),
+                PeerInfo {
+                    deployment_id: "site-origin".to_string(),
+                    ..peer("origin", "https://origin.example:9000")
+                },
+            )]),
+            ..Default::default()
+        };
+
+        // The origin's clock once jumped ten years ahead; the hybrid clock
+        // keeps allocating from there long after the clock was corrected.
+        let excursion = edit_generation_wall_clock() + 10 * 365 * 24 * 60 * 60 * 1_000_000_000;
+        let fence = ("site-origin".to_string(), excursion + 1);
+        assert!(peer_edit_fence_is_admissible(&state, "site-local", &fence));
+        record_applied_peer_edit_generation(&mut state, &fence.0, fence.1);
+
+        // The reverse delivery of the race: g arrives after g+1 landed.
+        // Without the fence it would commit last and roll g+1 back.
+        assert!(peer_edit_delivery_is_stale(&state, "site-origin", excursion));
+        // Equal generation (same edit's fan-out or a replay) still applies,
+        // as does the next edit.
+        assert!(!peer_edit_delivery_is_stale(&state, "site-origin", excursion + 1));
+        assert!(!peer_edit_delivery_is_stale(&state, "site-origin", excursion + 2));
+
+        // The window's exact boundary: a delivery trailing the mark by the
+        // full window is still fenced; one nanosecond further is not — that
+        // distance is no longer explicable by a genuine race, only by a
+        // forged mark or an excursion the origin has left behind.
+        let mark = fence.1;
+        // A straggler trailing by a concrete hour must still be fenced —
+        // pins the window's real magnitude, not just its symbolic boundary.
+        assert!(peer_edit_delivery_is_stale(&state, "site-origin", mark - 60 * 60 * 1_000_000_000));
+        assert!(peer_edit_delivery_is_stale(
+            &state,
+            "site-origin",
+            mark - PEER_EDIT_FENCE_STALENESS_WINDOW_NANOS
+        ));
+        assert!(!peer_edit_delivery_is_stale(
+            &state,
+            "site-origin",
+            mark - PEER_EDIT_FENCE_STALENESS_WINDOW_NANOS - 1
+        ));
+
+        // A pre-hybrid plain-counter origin trails such a mark by eons: it
+        // is not fenced (the rc.2-era downgrade case), it just runs
+        // unfenced until its counter regime catches up.
+        assert!(!peer_edit_delivery_is_stale(&state, "site-origin", 3));
+    }
+
     /// P1-15 review follow-up: a site that leaves the mesh drops below two
     /// peers, which clears its state object and restarts its generation
     /// counter at zero. A mark left over from its previous membership would

rustfs/src/admin/handlers/system.rs

@@ -417,6 +417,13 @@ struct SystemAdminDiscovery {
 struct ServerInfoResponse {
     info: InfoMessage,
     admin_discovery: SystemAdminDiscovery,
+    /// Startup bitrot algorithm self-test outcome (rustfs/backlog#1873):
+    /// `passed` (algorithms verified at boot), `failed` (a drifted hash
+    /// implementation — the process is serving with degraded integrity
+    /// checking unless `RUSTFS_BITROT_SELFTEST_STRICT` aborted it), or
+    /// `unknown` (not yet run or disabled).
+    #[serde(rename = "bitrotSelftest")]
+    bitrot_selftest: &'static str,
 }
 
 #[derive(Serialize)]
@@ -433,6 +440,14 @@ fn system_admin_discovery(usecase: &DefaultAdminUsecase) -> SystemAdminDiscovery
     }
 }
 
+fn bitrot_selftest_status_str() -> &'static str {
+    match crate::bitrot_selftest::bitrot_selftest_passed() {
+        Some(true) => "passed",
+        Some(false) => "failed",
+        None => "unknown",
+    }
+}
+
 #[async_trait::async_trait]
 impl Operation for ServerInfoHandler {
     async fn call(&self, req: S3Request<Body>, _params: Params<'_, '_>) -> S3Result<S3Response<(StatusCode, Body)>> {
@@ -464,6 +479,7 @@ impl Operation for ServerInfoHandler {
         let response = ServerInfoResponse {
             info,
             admin_discovery: system_admin_discovery(&usecase),
+            bitrot_selftest: bitrot_selftest_status_str(),
         };
 
         let data = serde_json::to_vec(&response).map_err(|e| {
@@ -1535,6 +1551,18 @@ mod tests {
         );
     }
 
+    /// The startup bitrot self-test outcome must surface in server info as one
+    /// of three closed-set strings, never an internal enum or a null
+    /// (rustfs/backlog#1873). This test pins the string mapping; whether the
+    /// process-global cell holds Some(true)/Some(false)/None is owned by
+    /// `crate::bitrot_selftest`'s own tests.
+    #[test]
+    fn bitrot_selftest_status_str_is_a_closed_set_of_operators_strings() {
+        let rendered = super::bitrot_selftest_status_str();
+        assert!(matches!(rendered, "passed" | "failed" | "unknown"));
+        assert_eq!(super::bitrot_selftest_status_str(), rendered);
+    }
+
     #[test]
     fn server_info_response_exposes_admin_discovery_paths() {
         let usecase = DefaultAdminUsecase::without_context();
@@ -1556,6 +1584,7 @@ mod tests {
                 pools: None,
             },
             admin_discovery: system_admin_discovery(&usecase),
+            bitrot_selftest: super::bitrot_selftest_status_str(),
         };
 
         let value = serde_json::to_value(response).expect("server info response should serialize");

rustfs/src/bitrot_selftest.rs

@@ -0,0 +1,181 @@
+// Copyright 2024 RustFS Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Startup bitrot algorithm self-test (rustfs/backlog#1873).
+//!
+//! A drifted hash implementation fails silently in production: every shard
+//! reads back "corrupt", heal rewrites healthy data, and cross-platform
+//! clusters disagree about which copy is good. [`run_startup_bitrot_self_test`]
+//! pins the algorithms once at process start — the check itself runs in well
+//! under a millisecond on 4 KiB, so it executes inline before background
+//! services come up and the result is published before the server accepts
+//! traffic.
+//!
+//! Outcome surface:
+//! - one structured `bitrot_selftest` log event (`passed`/`failed`/`skipped`),
+//! - the `rustfs_bitrot_selftest_status` gauge (1=passed, 0=failed, 2=skipped),
+//! - [`bitrot_selftest_passed`] for admin/health surfaces,
+//! - `RUSTFS_BITROT_SELFTEST_STRICT=on` turns a failure into a startup error
+//!   (MinIO `bitrotSelfTest` Fatal parity); the default only degrades the
+//!   status so a bad build cannot brick an existing fleet on upgrade.
+
+use crate::storage_api::startup::background::{BitrotSelfTestError, bitrot_self_test};
+use metrics::gauge;
+use std::future::Future;
+use std::io;
+use std::sync::atomic::{AtomicU8, Ordering};
+use std::time::Instant;
+use tracing::{debug, error, info};
+
+const LOG_COMPONENT_MAIN: &str = "main";
+const LOG_SUBSYSTEM_STARTUP: &str = "startup";
+const EVENT_BITROT_SELFTEST: &str = "bitrot_selftest";
+const METRIC_BITROT_SELFTEST_STATUS: &str = "rustfs_bitrot_selftest_status";
+
+/// Gauge values for [`METRIC_BITROT_SELFTEST_STATUS`].
+const STATUS_PASSED: f64 = 1.0;
+const STATUS_FAILED: f64 = 0.0;
+const STATUS_SKIPPED: f64 = 2.0;
+
+/// Internal cell values for [`BITROT_SELF_TEST_STATUS`].
+const STATUS_CELL_UNSET: u8 = 0;
+const STATUS_CELL_PASSED: u8 = 1;
+const STATUS_CELL_FAILED: u8 = 2;
+
+static BITROT_SELF_TEST_STATUS: AtomicU8 = AtomicU8::new(STATUS_CELL_UNSET);
+
+/// Last recorded self-test outcome: `None` before the first run, then
+/// `Some(true)` on a passing check and `Some(false)` on a failed one (a
+/// skipped check never publishes, so it cannot read as a pass). The cell is
+/// last-writer-wins rather than set-once: production runs the self-test once,
+/// and last-writer-wins keeps tests that exercise both outcomes
+/// order-independent.
+pub fn bitrot_selftest_passed() -> Option<bool> {
+    match BITROT_SELF_TEST_STATUS.load(Ordering::Acquire) {
+        STATUS_CELL_UNSET => None,
+        STATUS_CELL_PASSED => Some(true),
+        STATUS_CELL_FAILED => Some(false),
+        _ => None,
+    }
+}
+
+/// Run the bitrot self-test and publish the outcome. In strict mode a failure
+/// is returned as an error so the caller aborts startup.
+pub(crate) async fn run_startup_bitrot_self_test(enabled: bool, strict: bool) -> io::Result<()> {
+    run_startup_bitrot_self_test_with(enabled, strict, bitrot_self_test).await
+}
+
+async fn run_startup_bitrot_self_test_with<F, Fut>(enabled: bool, strict: bool, run_check: F) -> io::Result<()>
+where
+    F: FnOnce() -> Fut,
+    Fut: Future<Output = Result<(), BitrotSelfTestError>>,
+{
+    if !enabled {
+        gauge!(METRIC_BITROT_SELFTEST_STATUS).set(STATUS_SKIPPED);
+        debug!(
+            target: "rustfs::main::run",
+            event = EVENT_BITROT_SELFTEST,
+            component = LOG_COMPONENT_MAIN,
+            subsystem = LOG_SUBSYSTEM_STARTUP,
+            state = "skipped",
+            reason = "disabled",
+            "Bitrot self-test skipped"
+        );
+        return Ok(());
+    }
+
+    let started = Instant::now();
+    match run_check().await {
+        Ok(()) => {
+            BITROT_SELF_TEST_STATUS.store(STATUS_CELL_PASSED, Ordering::Release);
+            gauge!(METRIC_BITROT_SELFTEST_STATUS).set(STATUS_PASSED);
+            info!(
+                target: "rustfs::main::run",
+                event = EVENT_BITROT_SELFTEST,
+                component = LOG_COMPONENT_MAIN,
+                subsystem = LOG_SUBSYSTEM_STARTUP,
+                state = "passed",
+                duration_us = started.elapsed().as_micros() as u64,
+                "Bitrot self-test passed"
+            );
+        }
+        Err(err) => {
+            BITROT_SELF_TEST_STATUS.store(STATUS_CELL_FAILED, Ordering::Release);
+            gauge!(METRIC_BITROT_SELFTEST_STATUS).set(STATUS_FAILED);
+            error!(
+                target: "rustfs::main::run",
+                event = EVENT_BITROT_SELFTEST,
+                component = LOG_COMPONENT_MAIN,
+                subsystem = LOG_SUBSYSTEM_STARTUP,
+                state = "failed",
+                duration_us = started.elapsed().as_micros() as u64,
+                error = %err,
+                "Bitrot self-test failed"
+            );
+            if strict {
+                return Err(io::Error::other(format!("bitrot self-test failed: {err}")));
+            }
+        }
+    }
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{BITROT_SELF_TEST_STATUS, STATUS_CELL_UNSET, bitrot_selftest_passed, run_startup_bitrot_self_test_with};
+    use crate::storage_api::startup::background::BitrotSelfTestError;
+    use std::future::ready;
+    use std::sync::atomic::Ordering;
+
+    fn failing_check() -> impl Future<Output = Result<(), BitrotSelfTestError>> {
+        ready(Err(BitrotSelfTestError::RoundtripReadback {
+            algorithm: "HighwayHash256S",
+        }))
+    }
+
+    /// All scenarios run sequentially inside one test: the status cell is
+    /// process-global, so parallel per-scenario tests would race the reset and
+    /// read each other's outcomes (the exact order-dependent flake class this
+    /// module exists to avoid).
+    #[tokio::test]
+    async fn startup_self_test_publishes_outcome_and_strict_gates_abort() {
+        BITROT_SELF_TEST_STATUS.store(STATUS_CELL_UNSET, Ordering::Release);
+
+        // Skipped: publishes nothing, never fails, never aborts.
+        run_startup_bitrot_self_test_with(false, true, || async { Ok(()) })
+            .await
+            .expect("a disabled self-test must not fail even in strict mode");
+        assert_eq!(bitrot_selftest_passed(), None, "a skipped run must leave the status unset");
+
+        // Passing: publishes Some(true), never fails.
+        run_startup_bitrot_self_test_with(true, false, || async { Ok(()) })
+            .await
+            .expect("a passing check must never fail startup");
+        assert_eq!(bitrot_selftest_passed(), Some(true), "a passing run must publish Some(true)");
+
+        // Failing, non-strict: publishes Some(false) but startup continues.
+        run_startup_bitrot_self_test_with(true, false, failing_check)
+            .await
+            .expect("a failed check must not abort startup in non-strict mode");
+        assert_eq!(bitrot_selftest_passed(), Some(false), "a failing run must publish Some(false)");
+
+        // Failing, strict: startup error carries the failure and the published
+        // outcome stays a failure.
+        let err = run_startup_bitrot_self_test_with(true, true, failing_check)
+            .await
+            .expect_err("strict mode must turn a failed check into a startup error");
+        assert!(err.to_string().contains("bitrot self-test failed"));
+        assert_eq!(bitrot_selftest_passed(), Some(false));
+    }
+}

rustfs/src/lib.rs

@@ -76,6 +76,7 @@ pub mod allocator_reclaim;
 pub mod app;
 pub mod auth;
 pub mod auth_keystone;
+pub(crate) mod bitrot_selftest;
 pub mod capacity;
 pub mod cluster_snapshot;
 pub mod config;

rustfs/src/module_switches.rs

@@ -33,6 +33,8 @@ pub(crate) const ENV_SCANNER_ENABLED: &str = "RUSTFS_SCANNER_ENABLED";
 pub(crate) const ENV_SCANNER_ENABLED_DEPRECATED: &str = "RUSTFS_ENABLE_SCANNER";
 pub(crate) const ENV_HEAL_ENABLED: &str = "RUSTFS_HEAL_ENABLED";
 pub(crate) const ENV_HEAL_ENABLED_DEPRECATED: &str = "RUSTFS_ENABLE_HEAL";
+pub(crate) const ENV_BITROT_SELFTEST_ENABLE: &str = "RUSTFS_BITROT_SELFTEST_ENABLE";
+pub(crate) const ENV_BITROT_SELFTEST_STRICT: &str = "RUSTFS_BITROT_SELFTEST_STRICT";
 
 static AUDIT_MODULE_ENABLED: AtomicBool = AtomicBool::new(rustfs_config::DEFAULT_AUDIT_ENABLE);
 static NOTIFY_MODULE_ENABLED: AtomicBool = AtomicBool::new(rustfs_config::DEFAULT_NOTIFY_ENABLE);
@@ -47,6 +49,18 @@ pub(crate) fn heal_enabled_from_env() -> bool {
     get_env_bool_with_aliases(ENV_HEAL_ENABLED, &[ENV_HEAL_ENABLED_DEPRECATED], true)
 }
 
+/// Whether the startup bitrot algorithm self-test runs, defaulting to on
+/// (rustfs/backlog#1873).
+pub(crate) fn bitrot_selftest_enabled_from_env() -> bool {
+    rustfs_utils::get_env_bool(ENV_BITROT_SELFTEST_ENABLE, true)
+}
+
+/// Whether a failed bitrot self-test aborts startup instead of only logging
+/// and exposing a failed status, defaulting to off.
+pub(crate) fn bitrot_selftest_strict_from_env() -> bool {
+    rustfs_utils::get_env_bool(ENV_BITROT_SELFTEST_STRICT, false)
+}
+
 /// Last published audit-module state.
 pub fn is_audit_module_enabled() -> bool {
     AUDIT_MODULE_ENABLED.load(Ordering::Relaxed)

rustfs/src/startup_background.rs

@@ -12,7 +12,10 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use crate::module_switches::{heal_enabled_from_env, scanner_enabled_from_env};
+use crate::bitrot_selftest::run_startup_bitrot_self_test;
+use crate::module_switches::{
+    bitrot_selftest_enabled_from_env, bitrot_selftest_strict_from_env, heal_enabled_from_env, scanner_enabled_from_env,
+};
 use crate::storage_api::startup::background::{ECStore, set_workload_admission_snapshot_provider};
 use crate::workload_admission::RustFsWorkloadAdmissionSnapshotProvider;
 use rustfs_concurrency::WorkloadAdmissionSnapshotProvider;
@@ -27,6 +30,12 @@ const LOG_SUBSYSTEM_STARTUP: &str = "startup";
 const EVENT_BACKGROUND_SERVICES_CONFIGURED: &str = "background_services_configured";
 
 pub(crate) async fn init_background_service_runtime(store: Arc<ECStore>) -> Result<bool> {
+    // Pin the bitrot algorithms before anything can write or verify a shard:
+    // the check costs well under a millisecond, and in strict mode a drifted
+    // build must abort here rather than after it has touched data
+    // (rustfs/backlog#1873).
+    run_startup_bitrot_self_test(bitrot_selftest_enabled_from_env(), bitrot_selftest_strict_from_env()).await?;
+
     let _ = create_ahm_services_cancel_token();
 
     let enable_scanner = scanner_enabled_from_env();

rustfs/src/storage/storage_api.rs

@@ -569,6 +569,10 @@ pub(crate) mod ecstore_erasure {
     pub(crate) use rustfs_ecstore::api::erasure::{BitrotReader, Erasure};
 }
 
+/// Startup bitrot algorithm self-test (rustfs/backlog#1873), re-exported for
+/// the root facade's background-startup section.
+pub(crate) use rustfs_ecstore::api::erasure::{BitrotSelfTestError, bitrot_self_test};
+
 pub(crate) mod ecstore_storage {
     #[cfg(test)]
     pub(crate) use rustfs_ecstore::api::storage::init_local_disks;

rustfs/src/storage_api.rs

@@ -214,7 +214,9 @@ pub(crate) mod startup {
     }
 
     pub(crate) mod background {
-        pub(crate) use crate::storage::storage_api::{ECStore, set_workload_admission_snapshot_provider};
+        pub(crate) use crate::storage::storage_api::{
+            BitrotSelfTestError, ECStore, bitrot_self_test, set_workload_admission_snapshot_provider,
+        };
     }
 
     pub(crate) mod bucket_metadata {