How to find and change fnic queue depth ?

Solution Verified - Updated

Environment

  • Red Hat Enterprise Linux
  • Cisco UCS

Issue

  • What is default value of queue depth in fnic driver?
  • How to change queue depth of fnic driver?

Resolution

  • Default value of queue depth in fnic driver is 32

      cat /sys/block/sd<N>/device/queue_depth
  32

  • Except for the version(s) listed below, it is not possible to change queue depth of within the fnic driver. If there is a need to adjust the lun queue depth for devices serviced by the fnic driver then upgrade to one of the following kernel versions.

    • RHEL 6.7 or later (kernel 2.6.32-573.el6), which includes fnic driver version 1.6.0.17.
    • RHEL 7.2 or later (kernel 3.10.0-324.el7), which includes fnic driver version 1.6.0.17.
    • the following parameter was added to the driver within the above kernel versions, it cannot be changed dynamically during run-time
      • parm: fnic_max_qdepth:Queue depth to report for each LUN (uint)
    • To change the parameter on above versions (verify that it is shown in the output of modinfo fnic):
      • create /etc/modprobe.d/fnic-options.conf file with following line:
        • options fnic fnic_max_qdepth=<number>
      • rebuild initramfs to pick up new setting
      • reboot system
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