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Identify and Remove AIX and VIO Server Persistent Reservations

AIX and VIO servers can set persistent reservations in certain circumstances that can cause customer errors and problems when accessing those volumes.

Problem

Under some circumstances, AIX and VIO servers that discovered the FlashArray Volumes without a Pure Storage ODM definition in place will apply the default type  "Other FC SCSI disk drive", that defines the reserve_policy attribute as single_path.

After the Pure Storage ODM definition is installed, the volumes will be correctly identified as "PURE MPIO Drive", but a single_path reservation is likely to be set in the volume by then.

Impact

Customer will receive errors when paths other than the ones holding the reservation try to access the volume. Those errors will be of type SC_DISK_ERR and will contain a sense data where SS value is 18 (the SCSI device is reserved by another host):

SENSE DATA
0A00 2800 02E8 BA60 0000 2004 0000 0000 0000 0000 0000 0000 0118 0000 0000 0000

Solution

The solution is to remove the persistent reservation from the host using devrsrv replacing hdiskXX with the affected hdisk:

devrsrv -c release -l hdiskXX

It's possible to identify the persistent reservations in the array using puredb list reservation in conjunction with pslun_map and using the WWPN that is used on the reservation to identify which ports (and therefore host) has a reservation on which volume. An example in ES-50167.

References:
IBM Fibre Channel Planning & Integration: User's Guide & Service Information (SC23-4329-03)