Description : Changing LU Queue Depth on Vmware Host

Platform : VM Ware ESXi 5.x

Category : How-To

Procedure

In this document we will see how to change the queue depth for QLogic and Emulex HBAs on Vmware Host When we change the Queue Depth value If the performance of your hardware bus adapters (HBAs) is unsatisfactory, or your SAN storage processors or heads are over-utilized, you can adjust your ESXi/ESX hosts' maximum queue depth value. The maximum value refers to the queue depths reported for various paths to the LUN. When you lower this value, it throttles the ESXi/ESX host's throughput and alleviates SAN contention concerns if multiple hosts are over-utilizing the storage and are filling its command queue. When one virtual machine is active on a LUN, you only need to set the maximum queue depth. When multiple virtual machines are active on a LUN, the Disk.SchedNumReqOutstanding value is also relevant. The queue depth value, in this case, is equal to whichever value is the lowest of the two settings: adapter queue depth or Disk.SchedNumReqOutstanding. Procedure for ESXi 5.x To adjust the queue depth for an HBA: To Verify which HBA module is currently loaded by entering one of these commands on the service console: For QLogic: # esxcli system module list | grep qla For Emulex: # esxcli system module list | grep lpfc Note: The examples show the QLogic qla2xxx and Emulex lpfc820 modules. Use the appropriate module based on the outcome of the previous step. After identifying the HBA model Run one of these commands: For QLogic: # esxcli system module parameters set -p ql2xmaxqdepth=64 -m qla2xxx

For Emulex: # esxcli system module parameters set -p lpfc0_lun_queue_depth=64 -m lpfc820 Notes:

In these commands, both ql2xmaxqdepth and lpfc0 use the lowercase letter L, "l", and not the numeric digit 1.

In this case, the HBAs represented by ql2x and lpfc0 have their LUN queue depths set to 64.

If all Emulex cards on the host need to be updated, apply the global parameter, lpfc_lun_queue_depth instead.

Reboot your host. Run this command to confirm that your changes have been applied: # esxcli system module parameters list -m driver Where driver is your QLogic or Emulex adapter driver module, such as lpfc820 or qla2xxx. The output appears similar to: Name Type Value Description -------------------------- ---- ----- -------------------------------------------------- ..... ql2xmaxqdepth int 64 Maximum queue depth to report for target devices. .....