When using Active Cluster, PureStorage relies on ALUA to help provide information about path updates and failure statuses. One possible status report is the STANDBY status, which AIX only supports from AIX 7.3TL1 and above.
If using AIX versions previous to 7.3TL1 with FlashArray running Purity 6.1.24+, 6.2.1+, 6.3.8+, or 6.4.3+ and the host personality set to AIX, Pure Support can optionally configure the array so Purity sends an UNAVAILABLE response instead of a STANDBY response. This may prevent some scenarios where AIX may misinterpret the status of the paths.
There is a caveat associated switching to the UNAVAILABLE ALUA status: If an AIX system is rebooted while a pod is resyncing, the paths to the array will be marked as missing and it will require manual use of cfgmgr to recover the paths after the pod is in sync.
The tuning for this is available from PURE-273514 and is in Purity 6.1.24+, 6.2.1+, 6.3.8+, and 6.4.3+ and above. The tuning is as follows:
puretune --set PS_SYNCREP_FAIL_IO_RETURN_UNAVAILABLE_TARGETED 1 ES-#####