Performance Tuning - Chelsio Communications Terminator Series Installation And User Manual

Chapter XI. iSCSI PDU Offload Initiator
4.4.

Performance Tuning

Apply the performance settings mentioned in the
chapter before proceeding.
In case iSCSI Initiator IRQs pose a bottleneck for multiple connections, you can improve IOPS
performance using the steps mentioned below.
i. Enable iSCSI multi-queue. In 3.18+ kernels, add the below entry to the grub configuration
file and reboot the machine:
scsi_mod.use_blk_mq=1
ii. Run the performance tuning script to map iSCSI Initiator queues to different CPUs:
[root@host~]# t4_perftune.sh -Q iSCSI -n
iii. Load initiator driver:
[root@host~]# modprobe cxgb4i
iv. For MTU 9000, no additional configuration needed.
For MTU 1500, set the following parameters in the iSCSI configuration file
/etc/iscsi/iscsid.conf.
node.session.iscsi.InitialR2T = No
node.session.iscsi.ImmediateData = Yes
node.session.iscsi.FirstBurstLength = 8192
node.conn[0].iscsi.MaxRecvDataSegmentLength = 1024
node.conn[0].iscsi.MaxXmitDataSegmentLength = 1024
v. Login to multiple targets.
vi. Run IOPS test.
Chelsio Unified Wire for Linux
Performance Tuning section in the Unified Wire
196