You can set the disk scheduling mode and queue depth. If you modify a disk parameter, modify it on all disks in a log, Grid, or data disk group and modify the following disk settings on the hosts resident with the disks.
/sys/block/vdb/queue/max_hw_sectors_kb—Use the default value, which is larger than 1024.
echo 1024 > /sys/block/vdb/queue/hw_sector_size—Use the default value 512.
echo deadline > /sys/block/vdb/queue/scheduler.
/etc/iscsi/iscsid.conf—Set the value of node.session.cmds_max and node.session.queue_depth to 1024.
After you modify the disk settings, log out and relog in.
iscsiadm -m node –u