feat(scanner): add adaptive pacing controls (#3315)

* feat(scanner): add adaptive pacing controls

* fix(scanner): bound pacing delay status precision

---------

Co-authored-by: Henry Guo <marshawcoco@users.noreply.github.com>

crates/config/README.md

@@ -65,6 +65,8 @@ Current guidance:
 ## Scanner environment aliases
 
 - `RUSTFS_SCANNER_SPEED` (canonical, also accepts `MINIO_SCANNER_SPEED`)
+- `RUSTFS_SCANNER_DELAY` (canonical)
+- `RUSTFS_SCANNER_MAX_WAIT_SECS` (canonical)
 - `RUSTFS_SCANNER_CYCLE` (canonical, also accepts `MINIO_SCANNER_CYCLE`)
 - `RUSTFS_SCANNER_START_DELAY_SECS` (canonical)
 - `RUSTFS_DATA_SCANNER_START_DELAY_SECS` (deprecated alias for compatibility)

crates/config/src/constants/scanner.rs

@@ -20,6 +20,12 @@ pub const SCANNER_SUB_SYS: &str = "scanner";
 /// Scanner config key selecting the speed preset.
 pub const SCANNER_SPEED: &str = "speed";
 
+/// Scanner config key overriding the scanner sleep multiplier.
+pub const SCANNER_DELAY: &str = "delay";
+
+/// Scanner config key overriding the maximum scanner sleep in seconds.
+pub const SCANNER_MAX_WAIT: &str = "max_wait";
+
 /// Scanner config key overriding the cycle interval in seconds.
 pub const SCANNER_CYCLE: &str = "cycle";
 
@@ -68,6 +74,8 @@ pub const SCANNER_ALERT_EXCESS_FOLDERS: &str = "alert_excess_folders";
 /// Scanner config keys supported by the admin config subsystem.
 pub const SCANNER_KEYS: &[&str] = &[
     SCANNER_SPEED,
+    SCANNER_DELAY,
+    SCANNER_MAX_WAIT,
     SCANNER_CYCLE,
     SCANNER_START_DELAY,
     SCANNER_CYCLE_MAX_DURATION,
@@ -123,6 +131,15 @@ pub const ENV_SCANNER_CYCLE_MAX_DIRECTORIES: &str = "RUSTFS_SCANNER_CYCLE_MAX_DI
 /// - Example: `export RUSTFS_SCANNER_SPEED=slow`
 pub const ENV_SCANNER_SPEED: &str = "RUSTFS_SCANNER_SPEED";
 
+/// Environment variable that overrides the scanner sleep multiplier.
+/// - Example: `export RUSTFS_SCANNER_DELAY=30.0`
+pub const ENV_SCANNER_DELAY: &str = "RUSTFS_SCANNER_DELAY";
+
+/// Environment variable that overrides the maximum scanner sleep in seconds.
+/// - Unit: seconds (u64).
+/// - Example: `export RUSTFS_SCANNER_MAX_WAIT_SECS=15`
+pub const ENV_SCANNER_MAX_WAIT_SECS: &str = "RUSTFS_SCANNER_MAX_WAIT_SECS";
+
 /// Default scanner speed preset.
 pub const DEFAULT_SCANNER_SPEED: &str = "default";
 
@@ -237,7 +254,9 @@ pub const DEFAULT_SCANNER_INLINE_HEAL_ENABLE: bool = false;
 /// | `slow`    | 10x    | 15 seconds| 1 minute       |
 /// | `slowest` | 100x   | 15 seconds| 30 minutes     |
 ///
-/// The cycle interval can be overridden by `RUSTFS_SCANNER_CYCLE`.
+/// The sleep factor, max sleep, and cycle interval can be overridden by
+/// `RUSTFS_SCANNER_DELAY`, `RUSTFS_SCANNER_MAX_WAIT_SECS`, and
+/// `RUSTFS_SCANNER_CYCLE`.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
 pub enum ScannerSpeed {
     Fastest,

crates/ecstore/src/config/mod.rs

@@ -289,7 +289,7 @@ mod tests {
     use super::*;
     use rustfs_config::{
         DEFAULT_DELIMITER, DEFAULT_HEAL_BITROT_CYCLE_SECS, DEFAULT_SCANNER_SPEED, HEAL_BITROT_CYCLE, SCANNER_CYCLE_MAX_OBJECTS,
-        SCANNER_SPEED, SCANNER_SUB_SYS,
+        SCANNER_DELAY, SCANNER_MAX_WAIT, SCANNER_SPEED, SCANNER_SUB_SYS,
     };
 
     #[test]
@@ -318,6 +318,8 @@ mod tests {
             .expect("scanner defaults should exist");
 
         assert_eq!(scanner_kvs.get(SCANNER_SPEED), DEFAULT_SCANNER_SPEED);
+        assert_eq!(scanner_kvs.get(SCANNER_DELAY), "");
+        assert_eq!(scanner_kvs.get(SCANNER_MAX_WAIT), "");
         assert_eq!(scanner_kvs.get(SCANNER_CYCLE_MAX_OBJECTS), "0");
 
         let heal_kvs = cfg

crates/ecstore/src/config/scanner.rs

@@ -19,8 +19,8 @@ use rustfs_config::{
     DEFAULT_SCANNER_MAX_CONCURRENT_DISK_SCANS, DEFAULT_SCANNER_MAX_CONCURRENT_SET_SCANS, DEFAULT_SCANNER_SPEED,
     DEFAULT_SCANNER_YIELD_EVERY_N_OBJECTS, SCANNER_ALERT_EXCESS_FOLDERS, SCANNER_ALERT_EXCESS_VERSION_SIZE,
     SCANNER_ALERT_EXCESS_VERSIONS, SCANNER_BITROT_CYCLE, SCANNER_CACHE_SAVE_TIMEOUT, SCANNER_CYCLE,
-    SCANNER_CYCLE_MAX_DIRECTORIES, SCANNER_CYCLE_MAX_DURATION, SCANNER_CYCLE_MAX_OBJECTS, SCANNER_IDLE_MODE,
-    SCANNER_MAX_CONCURRENT_DISK_SCANS, SCANNER_MAX_CONCURRENT_SET_SCANS, SCANNER_SPEED, SCANNER_START_DELAY,
+    SCANNER_CYCLE_MAX_DIRECTORIES, SCANNER_CYCLE_MAX_DURATION, SCANNER_CYCLE_MAX_OBJECTS, SCANNER_DELAY, SCANNER_IDLE_MODE,
+    SCANNER_MAX_CONCURRENT_DISK_SCANS, SCANNER_MAX_CONCURRENT_SET_SCANS, SCANNER_MAX_WAIT, SCANNER_SPEED, SCANNER_START_DELAY,
     SCANNER_YIELD_EVERY_N_OBJECTS,
 };
 use std::sync::LazyLock;
@@ -32,6 +32,16 @@ pub static DEFAULT_KVS: LazyLock<KVS> = LazyLock::new(|| {
             value: DEFAULT_SCANNER_SPEED.to_owned(),
             hidden_if_empty: false,
         },
+        KV {
+            key: SCANNER_DELAY.to_owned(),
+            value: String::new(),
+            hidden_if_empty: true,
+        },
+        KV {
+            key: SCANNER_MAX_WAIT.to_owned(),
+            value: String::new(),
+            hidden_if_empty: true,
+        },
         KV {
             key: SCANNER_CYCLE.to_owned(),
             value: String::new(),

crates/scanner/src/runtime_config.rs

@@ -22,12 +22,13 @@ use rustfs_config::{
     DEFAULT_SCANNER_SPEED, DEFAULT_SCANNER_YIELD_EVERY_N_OBJECTS, ENV_SCANNER_ALERT_EXCESS_FOLDERS,
     ENV_SCANNER_ALERT_EXCESS_VERSION_SIZE, ENV_SCANNER_ALERT_EXCESS_VERSIONS, ENV_SCANNER_BITROT_CYCLE_SECS,
     ENV_SCANNER_CACHE_SAVE_TIMEOUT_SECS, ENV_SCANNER_CYCLE, ENV_SCANNER_CYCLE_MAX_DIRECTORIES,
-    ENV_SCANNER_CYCLE_MAX_DURATION_SECS, ENV_SCANNER_CYCLE_MAX_OBJECTS, ENV_SCANNER_IDLE_MODE,
-    ENV_SCANNER_MAX_CONCURRENT_DISK_SCANS, ENV_SCANNER_MAX_CONCURRENT_SET_SCANS, ENV_SCANNER_SPEED, ENV_SCANNER_START_DELAY_SECS,
-    ENV_SCANNER_YIELD_EVERY_N_OBJECTS, HEAL_BITROT_CYCLE, HEAL_SUB_SYS, SCANNER_ALERT_EXCESS_FOLDERS,
-    SCANNER_ALERT_EXCESS_VERSION_SIZE, SCANNER_ALERT_EXCESS_VERSIONS, SCANNER_BITROT_CYCLE, SCANNER_CACHE_SAVE_TIMEOUT,
-    SCANNER_CYCLE, SCANNER_CYCLE_MAX_DIRECTORIES, SCANNER_CYCLE_MAX_DURATION, SCANNER_CYCLE_MAX_OBJECTS, SCANNER_IDLE_MODE,
-    SCANNER_MAX_CONCURRENT_DISK_SCANS, SCANNER_MAX_CONCURRENT_SET_SCANS, SCANNER_SPEED, SCANNER_START_DELAY, SCANNER_SUB_SYS,
+    ENV_SCANNER_CYCLE_MAX_DURATION_SECS, ENV_SCANNER_CYCLE_MAX_OBJECTS, ENV_SCANNER_DELAY, ENV_SCANNER_IDLE_MODE,
+    ENV_SCANNER_MAX_CONCURRENT_DISK_SCANS, ENV_SCANNER_MAX_CONCURRENT_SET_SCANS, ENV_SCANNER_MAX_WAIT_SECS, ENV_SCANNER_SPEED,
+    ENV_SCANNER_START_DELAY_SECS, ENV_SCANNER_YIELD_EVERY_N_OBJECTS, HEAL_BITROT_CYCLE, HEAL_SUB_SYS,
+    SCANNER_ALERT_EXCESS_FOLDERS, SCANNER_ALERT_EXCESS_VERSION_SIZE, SCANNER_ALERT_EXCESS_VERSIONS, SCANNER_BITROT_CYCLE,
+    SCANNER_CACHE_SAVE_TIMEOUT, SCANNER_CYCLE, SCANNER_CYCLE_MAX_DIRECTORIES, SCANNER_CYCLE_MAX_DURATION,
+    SCANNER_CYCLE_MAX_OBJECTS, SCANNER_DELAY, SCANNER_IDLE_MODE, SCANNER_MAX_CONCURRENT_DISK_SCANS,
+    SCANNER_MAX_CONCURRENT_SET_SCANS, SCANNER_MAX_WAIT, SCANNER_SPEED, SCANNER_START_DELAY, SCANNER_SUB_SYS,
     SCANNER_YIELD_EVERY_N_OBJECTS, ScannerSpeed,
 };
 use rustfs_ecstore::config::{Config as ServerConfig, KVS};
@@ -40,6 +41,8 @@ use tracing::warn;
 
 const ENV_SCANNER_START_DELAY_SECS_DEPRECATED: &str = "RUSTFS_DATA_SCANNER_START_DELAY_SECS";
 const NO_DEFAULT_CYCLE_OVERRIDE: u64 = 0;
+const MAX_SCANNER_DELAY_FACTOR: f64 = 10_000.0;
+const SCANNER_DELAY_RANGE_REASON: &str = "expected scanner delay between 0 and 10000";
 
 static SCANNER_DEFAULT_CYCLE_SECS: AtomicU64 = AtomicU64::new(NO_DEFAULT_CYCLE_OVERRIDE);
 
@@ -55,10 +58,14 @@ pub enum ScannerRuntimeConfigSource {
     Default,
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq)]
 pub(crate) struct ScannerRuntimeConfig {
     pub(crate) speed: ScannerSpeed,
     pub(crate) speed_source: ScannerRuntimeConfigSource,
+    pub(crate) delay: f64,
+    pub(crate) delay_source: ScannerRuntimeConfigSource,
+    pub(crate) max_wait: Duration,
+    pub(crate) max_wait_source: ScannerRuntimeConfigSource,
     pub(crate) idle_mode: bool,
     pub(crate) idle_mode_source: ScannerRuntimeConfigSource,
     pub(crate) start_delay: Option<Duration>,
@@ -92,6 +99,10 @@ impl Default for ScannerRuntimeConfig {
         Self {
             speed: scanner_default_speed(),
             speed_source: ScannerRuntimeConfigSource::Default,
+            delay: scanner_default_speed().sleep_factor(),
+            delay_source: ScannerRuntimeConfigSource::Default,
+            max_wait: scanner_default_speed().max_sleep(),
+            max_wait_source: ScannerRuntimeConfigSource::Default,
             idle_mode: DEFAULT_SCANNER_IDLE_MODE,
             idle_mode_source: ScannerRuntimeConfigSource::Default,
             start_delay: None,
@@ -143,6 +154,8 @@ pub struct ScannerRuntimeConfigValue<T> {
 #[derive(Clone, Debug, Serialize)]
 pub struct ScannerRuntimeConfigStatus {
     pub speed: ScannerRuntimeConfigValue<String>,
+    pub delay: ScannerRuntimeConfigValue<f64>,
+    pub max_wait_seconds: ScannerRuntimeConfigValue<f64>,
     pub idle_mode: ScannerRuntimeConfigValue<bool>,
     pub start_delay_seconds: ScannerRuntimeConfigValue<Option<u64>>,
     pub cycle_interval_seconds: ScannerRuntimeConfigValue<u64>,
@@ -246,6 +259,27 @@ fn parse_config_speed(value: String) -> Result<ScannerSpeed, ScannerRuntimeConfi
     ScannerSpeed::parse_str(&value).ok_or_else(|| invalid_value(SCANNER_SPEED, value, "expected scanner speed preset"))
 }
 
+fn parse_config_delay(key: &'static str, value: String) -> Result<f64, ScannerRuntimeConfigError> {
+    let parsed = value
+        .parse::<f64>()
+        .map_err(|_| invalid_value(key, value.clone(), SCANNER_DELAY_RANGE_REASON))?;
+    if parsed.is_finite() && (0.0..=MAX_SCANNER_DELAY_FACTOR).contains(&parsed) {
+        Ok(parsed)
+    } else {
+        Err(invalid_value(key, value, SCANNER_DELAY_RANGE_REASON))
+    }
+}
+
+fn parse_env_delay(key: &'static str, value: String, fallback: f64) -> f64 {
+    match parse_config_delay(key, value.clone()) {
+        Ok(parsed) => parsed,
+        Err(_) => {
+            warn!(env = key, value, fallback, "Invalid scanner delay config, using derived value");
+            fallback
+        }
+    }
+}
+
 fn parse_config_bitrot_cycle(key: &'static str, value: String) -> Result<Option<Duration>, ScannerRuntimeConfigError> {
     match value.trim().to_ascii_lowercase().as_str() {
         "0" | "true" | "on" | "yes" => Ok(Some(Duration::ZERO)),
@@ -304,6 +338,10 @@ fn validate_persisted_scanner_runtime_config(config: &ServerConfig) -> Result<()
     if let Some(value) = config_value(scanner_kvs, SCANNER_SPEED, DEFAULT_SCANNER_SPEED) {
         parse_config_speed(value)?;
     }
+    if let Some(value) = config_value(scanner_kvs, SCANNER_DELAY, "") {
+        parse_config_delay(SCANNER_DELAY, value)?;
+    }
+    validate_optional_config_u64(scanner_kvs, SCANNER_MAX_WAIT, "")?;
     if let Some(value) = config_value(scanner_kvs, SCANNER_IDLE_MODE, DEFAULT_SCANNER_IDLE_MODE) {
         parse_config_bool(SCANNER_IDLE_MODE, value)?;
     }
@@ -341,6 +379,36 @@ fn lookup_speed(kvs: Option<&KVS>) -> Result<(ScannerSpeed, ScannerRuntimeConfig
     Ok((scanner_default_speed(), ScannerRuntimeConfigSource::Default))
 }
 
+fn lookup_delay(
+    kvs: Option<&KVS>,
+    speed: ScannerSpeed,
+    speed_source: ScannerRuntimeConfigSource,
+) -> Result<(f64, ScannerRuntimeConfigSource), ScannerRuntimeConfigError> {
+    let derived = speed.sleep_factor();
+    if let Some(value) = rustfs_utils::get_env_opt_str(ENV_SCANNER_DELAY) {
+        return Ok((parse_env_delay(ENV_SCANNER_DELAY, value, derived), ScannerRuntimeConfigSource::Env));
+    }
+    if let Some(value) = config_value(kvs, SCANNER_DELAY, "") {
+        return parse_config_delay(SCANNER_DELAY, value).map(|delay| (delay, ScannerRuntimeConfigSource::Config));
+    }
+    Ok((derived, speed_source))
+}
+
+fn lookup_max_wait(
+    kvs: Option<&KVS>,
+    speed: ScannerSpeed,
+    speed_source: ScannerRuntimeConfigSource,
+) -> Result<(Duration, ScannerRuntimeConfigSource), ScannerRuntimeConfigError> {
+    if let Some(secs) = rustfs_utils::get_env_opt_u64(ENV_SCANNER_MAX_WAIT_SECS) {
+        return Ok((Duration::from_secs(secs), ScannerRuntimeConfigSource::Env));
+    }
+    if let Some(value) = config_value(kvs, SCANNER_MAX_WAIT, "") {
+        return parse_config_u64(SCANNER_MAX_WAIT, value)
+            .map(|secs| (Duration::from_secs(secs), ScannerRuntimeConfigSource::Config));
+    }
+    Ok((speed.max_sleep(), speed_source))
+}
+
 fn lookup_optional_seconds(
     kvs: Option<&KVS>,
     key: &'static str,
@@ -437,6 +505,8 @@ pub(crate) fn lookup_scanner_runtime_config(
     let heal_kvs = heal_kvs(config);
     let heal_kvs = heal_kvs.as_ref();
     let (speed, speed_source) = lookup_speed(scanner_kvs)?;
+    let (delay, delay_source) = lookup_delay(scanner_kvs, speed, speed_source)?;
+    let (max_wait, max_wait_source) = lookup_max_wait(scanner_kvs, speed, speed_source)?;
     let (idle_mode, idle_mode_source) =
         lookup_bool(scanner_kvs, SCANNER_IDLE_MODE, ENV_SCANNER_IDLE_MODE, DEFAULT_SCANNER_IDLE_MODE)?;
     let (start_delay, start_delay_source) = lookup_start_delay(scanner_kvs)?;
@@ -542,6 +612,10 @@ pub(crate) fn lookup_scanner_runtime_config(
     Ok(ScannerRuntimeConfig {
         speed,
         speed_source,
+        delay,
+        delay_source,
+        max_wait,
+        max_wait_source,
         idle_mode,
         idle_mode_source,
         start_delay,
@@ -572,7 +646,7 @@ pub(crate) fn lookup_scanner_runtime_config(
 }
 
 fn apply_resolved_runtime_config(config: ScannerRuntimeConfig) {
-    SCANNER_SLEEPER.update_from_runtime_config(config.speed, config.idle_mode, config.yield_every_n_objects);
+    SCANNER_SLEEPER.update_from_runtime_config(config.delay, config.max_wait, config.idle_mode, config.yield_every_n_objects);
     if let Ok(mut guard) = SCANNER_RUNTIME_CONFIG.write() {
         *guard = config;
     }
@@ -614,6 +688,14 @@ pub fn scanner_runtime_config_status() -> ScannerRuntimeConfigStatus {
             value: config.speed.to_string(),
             source: config.speed_source,
         },
+        delay: ScannerRuntimeConfigValue {
+            value: config.delay,
+            source: config.delay_source,
+        },
+        max_wait_seconds: ScannerRuntimeConfigValue {
+            value: config.max_wait.as_secs_f64(),
+            source: config.max_wait_source,
+        },
         idle_mode: ScannerRuntimeConfigValue {
             value: config.idle_mode,
             source: config.idle_mode_source,
@@ -718,9 +800,10 @@ mod tests {
     use super::{ScannerRuntimeConfigSource, lookup_scanner_runtime_config, validate_scanner_runtime_config};
     use rustfs_config::{
         DEFAULT_DELIMITER, ENV_SCANNER_BITROT_CYCLE_SECS, ENV_SCANNER_CACHE_SAVE_TIMEOUT_SECS, ENV_SCANNER_CYCLE,
-        ENV_SCANNER_CYCLE_MAX_OBJECTS, ENV_SCANNER_SPEED, HEAL_BITROT_CYCLE, HEAL_SUB_SYS, SCANNER_BITROT_CYCLE,
-        SCANNER_CACHE_SAVE_TIMEOUT, SCANNER_CYCLE, SCANNER_CYCLE_MAX_DIRECTORIES, SCANNER_CYCLE_MAX_DURATION,
-        SCANNER_CYCLE_MAX_OBJECTS, SCANNER_IDLE_MODE, SCANNER_SPEED, SCANNER_SUB_SYS, ScannerSpeed,
+        ENV_SCANNER_CYCLE_MAX_OBJECTS, ENV_SCANNER_DELAY, ENV_SCANNER_MAX_WAIT_SECS, ENV_SCANNER_SPEED, HEAL_BITROT_CYCLE,
+        HEAL_SUB_SYS, SCANNER_BITROT_CYCLE, SCANNER_CACHE_SAVE_TIMEOUT, SCANNER_CYCLE, SCANNER_CYCLE_MAX_DIRECTORIES,
+        SCANNER_CYCLE_MAX_DURATION, SCANNER_CYCLE_MAX_OBJECTS, SCANNER_DELAY, SCANNER_IDLE_MODE, SCANNER_SPEED, SCANNER_SUB_SYS,
+        ScannerSpeed,
     };
     use rustfs_ecstore::config::{Config as ServerConfig, KVS};
     use serial_test::serial;
@@ -864,6 +947,42 @@ mod tests {
         });
     }
 
+    #[test]
+    fn scanner_runtime_config_validation_rejects_invalid_persisted_delay() {
+        let config = server_config_with_scanner(&[(SCANNER_DELAY, "-1")]);
+
+        let err = validate_scanner_runtime_config(&config).expect_err("persisted scanner delay should be validated");
+        assert!(err.to_string().contains("delay"));
+    }
+
+    #[test]
+    fn scanner_runtime_config_validation_rejects_excessive_persisted_delay() {
+        let config = server_config_with_scanner(&[(SCANNER_DELAY, "10000.1")]);
+
+        let err = validate_scanner_runtime_config(&config).expect_err("persisted scanner delay should be bounded");
+        assert!(err.to_string().contains("delay"));
+    }
+
+    #[test]
+    fn scanner_runtime_config_validation_accepts_delay_upper_bound() {
+        let config = server_config_with_scanner(&[(SCANNER_DELAY, "10000")]);
+
+        validate_scanner_runtime_config(&config).expect("delay upper bound should be accepted");
+    }
+
+    #[test]
+    #[serial]
+    fn scanner_runtime_config_uses_derived_delay_for_excessive_env_override() {
+        let config = server_config_with_scanner(&[(SCANNER_SPEED, "slow")]);
+
+        with_var(ENV_SCANNER_DELAY, Some("1e308"), || {
+            let resolved = lookup_scanner_runtime_config(Some(&config)).expect("scanner runtime config");
+
+            assert_eq!(resolved.delay, ScannerSpeed::Slow.sleep_factor());
+            assert_eq!(resolved.delay_source, ScannerRuntimeConfigSource::Env);
+        });
+    }
+
     #[test]
     fn scanner_runtime_config_validation_rejects_non_default_target() {
         let config = server_config_with_scanner_target("analytics", &[(SCANNER_SPEED, "slow")]);
@@ -892,4 +1011,67 @@ mod tests {
         });
         super::refresh_scanner_runtime_config_for_tests();
     }
+
+    #[test]
+    #[serial]
+    fn scanner_runtime_config_status_reports_persisted_pacing_overrides() {
+        let config = server_config_with_scanner(&[("delay", "3.5"), ("max_wait", "7")]);
+
+        with_var_unset("RUSTFS_SCANNER_DELAY", || {
+            with_var_unset("RUSTFS_SCANNER_MAX_WAIT_SECS", || {
+                let resolved = lookup_scanner_runtime_config(Some(&config)).expect("scanner runtime config");
+                super::apply_resolved_runtime_config(resolved);
+
+                let encoded =
+                    serde_json::to_value(super::scanner_runtime_config_status()).expect("scanner status should serialize");
+
+                assert_eq!(encoded["delay"]["value"], 3.5);
+                assert_eq!(encoded["delay"]["source"], "config");
+                assert_eq!(encoded["max_wait_seconds"]["value"], 7.0);
+                assert_eq!(encoded["max_wait_seconds"]["source"], "config");
+            });
+        });
+        super::refresh_scanner_runtime_config_for_tests();
+    }
+
+    #[test]
+    #[serial]
+    fn scanner_runtime_config_status_prefers_env_pacing_overrides() {
+        let config = server_config_with_scanner(&[("delay", "3.5"), ("max_wait", "7")]);
+
+        with_var("RUSTFS_SCANNER_DELAY", Some("1.25"), || {
+            with_var("RUSTFS_SCANNER_MAX_WAIT_SECS", Some("2"), || {
+                let resolved = lookup_scanner_runtime_config(Some(&config)).expect("scanner runtime config");
+                super::apply_resolved_runtime_config(resolved);
+
+                let encoded =
+                    serde_json::to_value(super::scanner_runtime_config_status()).expect("scanner status should serialize");
+
+                assert_eq!(encoded["delay"]["value"], 1.25);
+                assert_eq!(encoded["delay"]["source"], "env");
+                assert_eq!(encoded["max_wait_seconds"]["value"], 2.0);
+                assert_eq!(encoded["max_wait_seconds"]["source"], "env");
+            });
+        });
+        super::refresh_scanner_runtime_config_for_tests();
+    }
+
+    #[test]
+    #[serial]
+    fn scanner_runtime_config_status_preserves_subsecond_max_wait() {
+        let config = server_config_with_scanner(&[(SCANNER_SPEED, "fast")]);
+
+        with_var_unset(ENV_SCANNER_SPEED, || {
+            with_var_unset(ENV_SCANNER_MAX_WAIT_SECS, || {
+                let resolved = lookup_scanner_runtime_config(Some(&config)).expect("scanner runtime config");
+                super::apply_resolved_runtime_config(resolved);
+
+                let status = super::scanner_runtime_config_status();
+
+                assert!((status.max_wait_seconds.value - 0.1).abs() < f64::EPSILON);
+                assert_eq!(status.max_wait_seconds.source, ScannerRuntimeConfigSource::Config);
+            });
+        });
+        super::refresh_scanner_runtime_config_for_tests();
+    }
 }

crates/scanner/src/sleeper.rs

@@ -152,22 +152,32 @@ impl DynamicSleeper {
         }
     }
 
+    fn update_params(&self, factor: f64, max_sleep: Duration) {
+        let mut f = self.inner.factor.write().unwrap_or_else(|e| e.into_inner());
+        *f = factor;
+        let mut m = self.inner.max_sleep.write().unwrap_or_else(|e| e.into_inner());
+        *m = max_sleep;
+    }
+
     /// Swap in parameters from a new speed preset (for runtime reconfiguration).
     pub fn update(&self, speed: ScannerSpeed) {
-        let mut f = self.inner.factor.write().unwrap_or_else(|e| e.into_inner());
-        *f = speed.sleep_factor();
-        let mut m = self.inner.max_sleep.write().unwrap_or_else(|e| e.into_inner());
-        *m = speed.max_sleep();
+        self.update_params(speed.sleep_factor(), speed.max_sleep());
     }
 
     /// Reload speed and idle-mode settings from the current environment.
     pub fn refresh_from_env(&self) {
         let (speed, idle_mode) = scanner_env_config();
-        self.update_from_runtime_config(speed, idle_mode, scanner_yield_every_n_objects());
+        self.update_from_runtime_config(speed.sleep_factor(), speed.max_sleep(), idle_mode, scanner_yield_every_n_objects());
     }
 
-    pub(crate) fn update_from_runtime_config(&self, speed: ScannerSpeed, idle_mode: bool, yield_every_n_objects: u64) {
-        self.update(speed);
+    pub(crate) fn update_from_runtime_config(
+        &self,
+        sleep_factor: f64,
+        max_sleep: Duration,
+        idle_mode: bool,
+        yield_every_n_objects: u64,
+    ) {
+        self.update_params(sleep_factor, max_sleep);
         SCANNER_IDLE_MODE.store(idle_mode, Ordering::Relaxed);
         self.record_throttle_config_with_yield(yield_every_n_objects);
     }
@@ -264,6 +274,21 @@ mod tests {
         assert_eq!(max_sleep, Duration::from_secs(15));
     }
 
+    #[test]
+    fn test_update_from_runtime_config_applies_explicit_pacing_params() {
+        let prev_mode = SCANNER_IDLE_MODE.load(Ordering::Relaxed);
+        let s = DynamicSleeper::new(ScannerSpeed::Default);
+
+        s.update_from_runtime_config(3.5, Duration::from_secs(7), true, 64);
+
+        let (factor, max_sleep) = s.read_params();
+        assert_eq!(factor, 3.5);
+        assert_eq!(max_sleep, Duration::from_secs(7));
+        assert!(SCANNER_IDLE_MODE.load(Ordering::Relaxed));
+
+        SCANNER_IDLE_MODE.store(prev_mode, Ordering::Relaxed);
+    }
+
     #[test]
     #[serial]
     fn test_refresh_from_env_applies_speed_and_idle_mode_for_next_cycle() {

rustfs/src/admin/handlers/config_admin.rs

@@ -52,14 +52,15 @@ use rustfs_config::{
     COMMENT_KEY, DEFAULT_DELIMITER, ENABLE_KEY, ENV_PREFIX, ENV_SCANNER_ALERT_EXCESS_FOLDERS,
     ENV_SCANNER_ALERT_EXCESS_VERSION_SIZE, ENV_SCANNER_ALERT_EXCESS_VERSIONS, ENV_SCANNER_BITROT_CYCLE_SECS,
     ENV_SCANNER_CACHE_SAVE_TIMEOUT_SECS, ENV_SCANNER_CYCLE, ENV_SCANNER_CYCLE_MAX_DIRECTORIES,
-    ENV_SCANNER_CYCLE_MAX_DURATION_SECS, ENV_SCANNER_CYCLE_MAX_OBJECTS, ENV_SCANNER_IDLE_MODE,
-    ENV_SCANNER_MAX_CONCURRENT_DISK_SCANS, ENV_SCANNER_MAX_CONCURRENT_SET_SCANS, ENV_SCANNER_SPEED, ENV_SCANNER_START_DELAY_SECS,
-    ENV_SCANNER_YIELD_EVERY_N_OBJECTS, HEAL_BITROT_CYCLE, HEAL_SUB_SYS, MAX_ADMIN_REQUEST_BODY_SIZE, MQTT_BROKER,
-    MQTT_KEEP_ALIVE_INTERVAL, MQTT_PASSWORD, MQTT_QOS, MQTT_QUEUE_DIR, MQTT_QUEUE_LIMIT, MQTT_RECONNECT_INTERVAL, MQTT_TOPIC,
-    MQTT_USERNAME, SCANNER_ALERT_EXCESS_FOLDERS, SCANNER_ALERT_EXCESS_VERSION_SIZE, SCANNER_ALERT_EXCESS_VERSIONS,
-    SCANNER_BITROT_CYCLE, SCANNER_CACHE_SAVE_TIMEOUT, SCANNER_CYCLE, SCANNER_CYCLE_MAX_DIRECTORIES, SCANNER_CYCLE_MAX_DURATION,
-    SCANNER_CYCLE_MAX_OBJECTS, SCANNER_IDLE_MODE, SCANNER_MAX_CONCURRENT_DISK_SCANS, SCANNER_MAX_CONCURRENT_SET_SCANS,
-    SCANNER_SPEED, SCANNER_START_DELAY, SCANNER_SUB_SYS, SCANNER_YIELD_EVERY_N_OBJECTS, WEBHOOK_AUTH_TOKEN, WEBHOOK_BATCH_SIZE,
+    ENV_SCANNER_CYCLE_MAX_DURATION_SECS, ENV_SCANNER_CYCLE_MAX_OBJECTS, ENV_SCANNER_DELAY, ENV_SCANNER_IDLE_MODE,
+    ENV_SCANNER_MAX_CONCURRENT_DISK_SCANS, ENV_SCANNER_MAX_CONCURRENT_SET_SCANS, ENV_SCANNER_MAX_WAIT_SECS, ENV_SCANNER_SPEED,
+    ENV_SCANNER_START_DELAY_SECS, ENV_SCANNER_YIELD_EVERY_N_OBJECTS, HEAL_BITROT_CYCLE, HEAL_SUB_SYS,
+    MAX_ADMIN_REQUEST_BODY_SIZE, MQTT_BROKER, MQTT_KEEP_ALIVE_INTERVAL, MQTT_PASSWORD, MQTT_QOS, MQTT_QUEUE_DIR,
+    MQTT_QUEUE_LIMIT, MQTT_RECONNECT_INTERVAL, MQTT_TOPIC, MQTT_USERNAME, SCANNER_ALERT_EXCESS_FOLDERS,
+    SCANNER_ALERT_EXCESS_VERSION_SIZE, SCANNER_ALERT_EXCESS_VERSIONS, SCANNER_BITROT_CYCLE, SCANNER_CACHE_SAVE_TIMEOUT,
+    SCANNER_CYCLE, SCANNER_CYCLE_MAX_DIRECTORIES, SCANNER_CYCLE_MAX_DURATION, SCANNER_CYCLE_MAX_OBJECTS, SCANNER_DELAY,
+    SCANNER_IDLE_MODE, SCANNER_MAX_CONCURRENT_DISK_SCANS, SCANNER_MAX_CONCURRENT_SET_SCANS, SCANNER_MAX_WAIT, SCANNER_SPEED,
+    SCANNER_START_DELAY, SCANNER_SUB_SYS, SCANNER_YIELD_EVERY_N_OBJECTS, WEBHOOK_AUTH_TOKEN, WEBHOOK_BATCH_SIZE,
     WEBHOOK_CLIENT_CERT, WEBHOOK_CLIENT_KEY, WEBHOOK_ENDPOINT, WEBHOOK_HTTP_TIMEOUT, WEBHOOK_MAX_RETRY, WEBHOOK_QUEUE_DIR,
     WEBHOOK_QUEUE_LIMIT, WEBHOOK_RETRY_INTERVAL,
 };
@@ -192,6 +193,18 @@ const SCANNER_HELP_KEYS: &[HelpKeyMetadata] = &[
         description: "set scanner throttling preset",
         optional: true,
     },
+    HelpKeyMetadata {
+        key: SCANNER_DELAY,
+        type_name: "float",
+        description: "override scanner sleep multiplier derived from speed",
+        optional: true,
+    },
+    HelpKeyMetadata {
+        key: SCANNER_MAX_WAIT,
+        type_name: "seconds",
+        description: "override scanner maximum sleep duration derived from speed",
+        optional: true,
+    },
     HelpKeyMetadata {
         key: SCANNER_CYCLE,
         type_name: "seconds",
@@ -1322,6 +1335,8 @@ fn env_help_key(sub_system: &str, key: &str) -> String {
         (STORAGE_CLASS_SUB_SYS, "optimize") => OPTIMIZE_ENV.to_string(),
         (STORAGE_CLASS_SUB_SYS, "inline_block") => INLINE_BLOCK_ENV.to_string(),
         (SCANNER_SUB_SYS, SCANNER_SPEED) => ENV_SCANNER_SPEED.to_string(),
+        (SCANNER_SUB_SYS, SCANNER_DELAY) => ENV_SCANNER_DELAY.to_string(),
+        (SCANNER_SUB_SYS, SCANNER_MAX_WAIT) => ENV_SCANNER_MAX_WAIT_SECS.to_string(),
         (SCANNER_SUB_SYS, SCANNER_CYCLE) => ENV_SCANNER_CYCLE.to_string(),
         (SCANNER_SUB_SYS, SCANNER_START_DELAY) => ENV_SCANNER_START_DELAY_SECS.to_string(),
         (SCANNER_SUB_SYS, SCANNER_CYCLE_MAX_DURATION) => ENV_SCANNER_CYCLE_MAX_DURATION_SECS.to_string(),
@@ -1990,6 +2005,25 @@ identity_openid config_url="https://issuer.example" client_id="console""#,
         assert!(response.keys_help[0].description.contains("cycle"));
     }
 
+    #[test]
+    fn validate_config_directives_accepts_scanner_pacing_keys() {
+        let input = format!("{SCANNER_SUB_SYS} {SCANNER_DELAY}=\"3.5\" {SCANNER_MAX_WAIT}=\"7\"");
+        let directives = parse_config_directives(&input, false).expect("parse scanner pacing directive");
+
+        validate_config_directives(&directives).expect("scanner pacing keys should be supported");
+    }
+
+    #[test]
+    fn build_help_response_reports_scanner_delay() {
+        let response = build_help_response(Some(SCANNER_SUB_SYS), Some(SCANNER_DELAY), false).expect("scanner help response");
+
+        assert_eq!(response.sub_sys, SCANNER_SUB_SYS);
+        assert_eq!(response.keys_help.len(), 1);
+        assert_eq!(response.keys_help[0].key, SCANNER_DELAY);
+        assert_eq!(response.keys_help[0].type_name, "float");
+        assert!(response.keys_help[0].description.contains("multiplier"));
+    }
+
     #[test]
     fn validate_config_directives_accepts_heal_bitrot_cycle() {
         let input = format!("{HEAL_SUB_SYS} {HEAL_BITROT_CYCLE}=\"off\"");