White Papers

Administration best practices
24 Dell EMC PowerVault ME4 Series and Microsoft Hyper-V | 3921-BP-WS
hosts all competing for a few target ports, increasing the queue depth on a few hosts might overdrive the
target ports and negatively impact the performance of all connected hosts.
While increasing the queue depth can sometimes increase performance significantly for specific workloads, if
it is set too high, there is an increased risk of overdriving the target ports on the storage array. Generally, if
transactions are being queued and performance is being impacted, and increasing the queue depth results in
saturation of the target ports, then increasing the number of initiators and targets (if available) to spread out
I/O can be an effective remediation.
3.8.2 Vendor-specific HBA and CNA queue depth settings
It is very important to understand the firmware and miniport driver registry settings for the host server FC
HBA, iSCSI NIC, or CNA adapter and how these settings affect queue depth. In the case of QLogic
®
FC
HBAs, for example, the execution throttle setting can be adjusted to control queue depth.
For direction on adjusting firmware or registry settings to modify queue depth, see the documentation for your
FC HBA, iSCSI NIC, or CNA.
Note: Changes to FC HBA, iSCSI NIC, or CNA firmware or registry settings that affect queue depth should be
evaluated in a test environment prior to implementation on production workloads.