config: add mmap read env alias (#4021)

crates/ecstore/src/io_support/bitrot.rs

@@ -15,6 +15,7 @@
 use crate::disk::{self, DiskAPI as _, DiskStore, FileReader, error::DiskError};
 use crate::erasure::coding::{BitrotReader, BitrotWriterWrapper, CustomWriter};
 use bytes::Bytes;
+use rustfs_config::{DEFAULT_OBJECT_MMAP_READ_ENABLE, ENV_OBJECT_MMAP_READ_ENABLE, ENV_OBJECT_ZERO_COPY_ENABLE};
 use rustfs_utils::HashAlgorithm;
 use std::future::Future;
 use std::io::{self, Cursor};
@@ -28,6 +29,14 @@ use tracing::debug;
 type BoxedObjectReader = Box<dyn AsyncRead + Send + Sync + Unpin>;
 type OpenObjectReaderFuture = Pin<Box<dyn Future<Output = disk::error::Result<Option<BoxedObjectReader>>> + Send>>;
 
+pub(crate) fn object_mmap_read_enabled() -> bool {
+    rustfs_utils::get_env_bool_with_aliases(
+        ENV_OBJECT_MMAP_READ_ENABLE,
+        &[ENV_OBJECT_ZERO_COPY_ENABLE],
+        DEFAULT_OBJECT_MMAP_READ_ENABLE,
+    )
+}
+
 #[derive(Clone)]
 struct BitrotReaderSource {
     inline_data: Option<Bytes>,
@@ -295,6 +304,32 @@ pub async fn create_bitrot_writer(
 mod tests {
     use super::*;
 
+    #[test]
+    fn object_mmap_read_enabled_accepts_legacy_zero_copy_alias() {
+        temp_env::with_vars(
+            [
+                (ENV_OBJECT_MMAP_READ_ENABLE, None::<&str>),
+                (ENV_OBJECT_ZERO_COPY_ENABLE, Some("false")),
+            ],
+            || {
+                assert!(!object_mmap_read_enabled());
+            },
+        );
+    }
+
+    #[test]
+    fn object_mmap_read_enabled_prefers_canonical_env() {
+        temp_env::with_vars(
+            [
+                (ENV_OBJECT_MMAP_READ_ENABLE, Some("true")),
+                (ENV_OBJECT_ZERO_COPY_ENABLE, Some("false")),
+            ],
+            || {
+                assert!(object_mmap_read_enabled());
+            },
+        );
+    }
+
     #[tokio::test]
     async fn test_create_bitrot_reader_with_inline_data() {
         let test_data = b"hello world test data";

crates/ecstore/src/set_disk/heal.rs

@@ -13,8 +13,8 @@
 // limitations under the License.
 
 use super::*;
+use crate::io_support::bitrot::object_mmap_read_enabled;
 use crate::storage_api_contracts::namespace::NamespaceLocking as _;
-use rustfs_config::{DEFAULT_OBJECT_ZERO_COPY_ENABLE, ENV_OBJECT_ZERO_COPY_ENABLE};
 
 const LOG_COMPONENT_ECSTORE: &str = "ecstore";
 const LOG_SUBSYSTEM_HEAL: &str = "heal";
@@ -360,10 +360,7 @@ impl SetDisks {
 
                             for (part_index, part) in latest_meta.parts.iter().enumerate() {
                                 let till_offset = erasure.shard_file_offset(0, part.size, part.size);
-                                // Read zero-copy configuration from environment variable
-                                // Default: enabled (true) for performance
-                                let use_mmap_read =
-                                    rustfs_utils::get_env_bool(ENV_OBJECT_ZERO_COPY_ENABLE, DEFAULT_OBJECT_ZERO_COPY_ENABLE);
+                                let use_mmap_read = object_mmap_read_enabled();
 
                                 let mut readers = Vec::with_capacity(latest_disks.len());
                                 let mut writers = Vec::with_capacity(out_dated_disks.len());

crates/ecstore/src/set_disk/read.rs

@@ -26,11 +26,10 @@ use crate::diagnostics::get::{
     record_get_object_pipeline_failure_for_path, record_get_stage_duration_if_enabled,
 };
 use crate::erasure::coding::BitrotReader;
-use crate::io_support::bitrot::create_deferred_bitrot_reader;
+use crate::io_support::bitrot::{create_deferred_bitrot_reader, object_mmap_read_enabled};
 use crate::set_disk::shard_source::ShardReadCost;
 use futures::stream::{FuturesUnordered, StreamExt};
 use metrics::counter;
-use rustfs_config::{DEFAULT_OBJECT_ZERO_COPY_ENABLE, ENV_OBJECT_ZERO_COPY_ENABLE};
 use std::{
     collections::{HashMap, VecDeque},
     future::Future,
@@ -2004,9 +2003,7 @@ impl SetDisks {
             };
             let read_length = till_offset.saturating_sub(read_offset);
 
-            // Read zero-copy configuration from environment variable
-            // Default: enabled (true) for performance
-            let use_mmap_read = rustfs_utils::get_env_bool(ENV_OBJECT_ZERO_COPY_ENABLE, DEFAULT_OBJECT_ZERO_COPY_ENABLE);
+            let use_mmap_read = object_mmap_read_enabled();
 
             let reader_setup_stage_start = Instant::now();
             let read_costs = disks
@@ -2387,7 +2384,7 @@ impl SetDisks {
         } else {
             checksum_info.algorithm
         };
-        let use_mmap_read = rustfs_utils::get_env_bool(ENV_OBJECT_ZERO_COPY_ENABLE, DEFAULT_OBJECT_ZERO_COPY_ENABLE);
+        let use_mmap_read = object_mmap_read_enabled();
         let till_offset = erasure.shard_file_offset(part_offset, part_length, part_size);
         let read_offset = (part_offset / erasure.block_size) * erasure.shard_size();
         let read_length = till_offset.saturating_sub(read_offset);