Failure due to mismatch in device parameter "Max Outstanding IOs" when upgrading to ESXi 6.7

Products

• VMware vCenter Server

Issue/Introduction

Symptoms:

• Host Profile Compliance Failure.
• When upgrading to vSphere to 6.7 GA, there could be a compliance failure due to the mismatch of device parameter "Max Outstanding IOs" between ESXi 6.7.
• During stateless upgrades, the host could enter maintenance mode due to the compliance failure.
• The parameter can be found in Storage configuration > Pluggable Storage Architecture configuration > PSA device configuration > name of the device.

Environment

VMware vCenter Server 6.0.x
VMware vCenter Server 6.5.x
VMware vCenter Server 6.7.x

Cause

vSphere ESXi 6.5 onwards, setting of the "Max Outstanding IOs" parameter in host profiles is limited to Max Queue Depth of the device as the host should not be queueing more than the allowed device queue depth as this could lead to command failures.

"Max Outstanding IOs" is restricted to the Max Queue Depth of the device in 6.7. The default value of "Max Outstanding IOs" is 32 if not configured by user. For some devices like CD-ROM, the Max Queue Depth is lesser than the default value of 32. In prior releases 6.0 and 6.5, "Max Outstanding IOs" was not honoring the Max Queue Depth of the device. Therefore in prior releases, for some devices, there could be a case of "Max Outstanding IOs" greater than the Max Queue Depth of the device.

Resolution

Currently, there is no resolution

Workaround:
To workaround this issue:

1. Login into the vSphere web client.
2. Click on Host profiles 
3. Select Storage configuration > Pluggable Storage Architecture configuration > PSA device configuration > name of the device 
4. Edit the parameter "Max Outstanding IOs" and set the value between 1 and Max Queue Depth of the device.
5. Do a compliance check and remediate after editing the profile value.