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Updating Emulex HBA queue depths on a Linux host

You can update the queue depths of an Emulex HBA on a Linux host. To make the updates persistent across reboots, you must then create a new RAM disk image and reboot the host.

  1. Identify the queue depth parameters to be modified: modinfo lpfc|grep queue_depth

    The list of queue depth parameters with their description is displayed. Depending on your operating system version, you can modify one or more of the following queue depth parameters:

    • lpfc_lun_queue_depth: Maximum number of FC commands that can be queued to a specific LUN (uint)

    • lpfc_hba_queue_depth: Maximum number of FC commands that can be queued to an lpfc HBA (uint)

    • lpfc_tgt_queue_depth: Maximum number of FC commands that can be queued to a specific target port (uint)

      The lpfc_tgt_queue_depth parameter is applicable only for Red Hat Enterprise Linux 7.x systems, SUSE Linux Enterprise Server 11 SP4 systems and 12.x systems.

  2. Update the queue depths by adding the queue depth parameters to the /etc/modprobe.conf file for a Red Hat Enterprise Linux 5.x system and to the /etc/modprobe.d/scsi.conf file for a Red Hat Enterprise Linux 6.x or 7.x system, or a SUSE Linux Enterprise Server 11.x or 12.x system.

    Depending on your operating system version, you can add one or more of the following commands:
    • options lpfc lpfc_hba_queue_depth=new_queue_depth
    • options lpfc lpfc_lun_queue_depth=new_queue_depth
    • options lpfc_tgt_queue_depth=new_queue_depth
  3. Create a new RAM disk image, and then reboot the host to make the updates persistent across reboots.

    For more information, see the System Administration Reference Guide for your version of Linux operating system.
  4. Verify that the queue depth values are updated for each of the queue depth parameter that you have modified: cat /sys/class/scsi_host/host_number/lpfc_lun_queue_depth cat /sys/class/scsi_host/host_number/lpfc_tgt_queue_depth cat /sys/class/scsi_host/host_number/lpfc_hba_queue_depth

    Example

    root@localhost ~]#cat /sys/class/scsi_host/host5/lpfc_lun_queue_depth
          30
    The current value of the queue depth is displayed.