zvol_os.c: Increase optimal IO size

Since zvol read and write can process up to (DMU_MAX_ACCESS / 2) bytes in a single operation, the current optimal I/O size is too low. SCST directly reports this value as the optimal transfer length for the target SCSI device. Increasing it from the previous volblocksize results in performance improvement for VDIv2 workloads. Signed-off-by: Ameer Hamza <[email protected]>
truenas · Nov 13, 2024 · f8a5c09 · f8a5c09
1 parent 46c4f2c
commit f8a5c09
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
@@ -1176,7 +1176,7 @@ 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 =