When listing NMP PSP configuration, you may see "Path Selection Policy Path Config: PSP VMW_PSP_RR does not support path configuration" when PSP is set to Round Robin

Products

• VMware

Issue/Introduction

This article is referencing to the output you might find when reviewing NMP settings on storage devices from the ESXi command line, using commands like: 

esxcli storage nmp path list

Since 2008, ESX and ESXi builds from 4.0 and beyond, have included a "does not support path configuration" response when requesting specific information on Path Selection Policy Path Configuration settings or Storage Array Type Path Config parameters on Path Selection Policies that cannot use such configurations.

For the focus of the article, we are referring to the Round Robin response of "PSP VMW_PSP_RR does not support path configuration." It is important to know, that this message is not an error.

The messaging is to state that this configuration setting is not allowed with the Path Selection Policy, in this example, Round Robin.

The reason for this response, in this situation, is because path specific settings are not applicable to a path selection policy that rotates between multiple paths. In other words, you cannot have a single path configuration on a rotating path selection policy that will use multiple paths.

A configuration, such as IOP=1, the setting that controls how many IOPS should be done before moving to the next path, is instead an overall Path Selection Policy configuration, not a specific path configuration.

Further, you may see likewise messages on other configurations, such as SATP_DEFAULT_AA, which is an SATP configuration, that also may state that it does not support any Storage Array Type Path Config settings. This is also not an error and is purely informational in purpose.

Resolution

This message is working as intended and is not an error. You will see this message on any requests to list NMP settings on an attached LUN that is configured with Round Robin.