VMware Path Selection Policies (PSP)

Overview

Which PSP does DataCore Software recommend?

DataCore do not recommend any specific PSP. Choose the PSP that is appropriate for your configuration (refer to the compatibility lists). Depending on which PSP is chosen will affect which ‘Preferred Server’ setting should be used.

When to Modify an Existing PSP?

If the PSP can use the same SATP as the original setting, then nothing more needs to be done. If the PSP does not use the same SATP as before then DataCore recommends that all virtual disks are unserved from the ESXi host before changing the PSP.

How to Modify an Existing SATP Rule?

To change (or modify) the SATP for an existing PSP, DataCore recommends that the virtual disks are first unserved from the ESXi host. The original SATP must then be removed and the new SATP must be applied before re-serving the virtual disks back to the host.

See the following example which shows how to delete and recreate an existing SATP rule.

Also see:

Changing a LUN to Use a Different Path Selection Policy (PSP)

Changing Multipath or ALUA Support Settings for Hosts

Moving from Most Recently Used (MRU) to a different PSP

An example showing how to delete and recreate an existing SATP rule

1. List all SATP ALUA rules and identify those with DataCore Virtual Disk entries:

   esxcli storage nmp satp rule list -s VMW_SATP_ALUA

   
   

2. Remove the existing/old rule:

   esxcli storage nmp satp rule remove -V DataCore -M "Virtual Disk" -s VMW_SATP_ALUA -P VMW_PSP_RR -O iops=10 -c tpgs_on

   
   

3. Add the new rule:

   esxcli storage nmp satp rule add --vendor="DataCore" --model="Virtual Disk" --satp="VMW_SATP_ALUA" --psp="VMW_PSP_RR" --psp-option="iops=10" --option="disable_action_OnRetryErrors" --claim-option="tpgs_on" --description="DataCore SANsymphony ALUA RR"

4. Verify the change:

   esxcli storage nmp satp rule list -s VMW_SATP_ALUA