zvol_os.c: Increase optimal IO size

Since zvol read and write operations can process up to (DMU_MAX_ACCESS / 2) bytes in a single operation, the current optimal I/O size is set too low. SCST directly reports this value as the optimal transfer length for the target SCSI device. Increasing it from the previous volblocksize significantly improves performance for VDIv2 workloads. Signed-off-by: Ameer Hamza <[email protected]>
truenas · Nov 13, 2024 · a42ca2c · a42ca2c
1 parent ce92af2
commit a42ca2c
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/module/os/linux/zfs/zvol_os.c b/module/os/linux/zfs/zvol_os.c
@@ -1193,7 +1193,7 @@ zvol_queue_limits_init(zvol_queue_limits_t *limits, zvol_state_t *zv,
 		limits->zql_max_segment_size = UINT_MAX;
 	}
 
-	limits->zql_io_opt = zv->zv_volblocksize;
+	limits->zql_io_opt = DMU_MAX_ACCESS/2;
 
 	limits->zql_physical_block_size = zv->zv_volblocksize;
 	limits->zql_max_discard_sectors =