AIX Still Issues Single-Path Reservation When ODM is Set to no_reserve

Symptom

No known changes to host were made.
Path failure
Paths entering ASB:IOPF 
SC_DISK_ERR9 and SC_DISK_ERR10 with sense data 0118 
Reserve conflicts
devrsrv -c query -l hdiskXX returns ODM no_reserve but actual reserve of single_path
LABEL:        SC_DISK_ERR9
IDENTIFIER:    B0EE9AF5
Resource Name:   hdisk1024
Description
REQUESTED OPERATION CANNOT BE PERFORMED
SENSE DATA
0A00 2500 0000 0000 0000 0004 0000 0000 0000 0000 0000 0000 0118 0000 0000 0000 
lsattr -El hdisk527 :-
pvid           00c3a085229ab91a0000000000000000 Physical volume identifier       False
reserve_policy no_reserve                       Reserve Policy                   True
lsattr -El hdisk536 :-
pvid           00c3a085229ab91a0000000000000000 Physical volume identifier       False
reserve_policy no_reserve                       Reserve Policy                   True
lsattr -El hdisk563 :-
pvid           00c3a085229ab91a0000000000000000 Physical volume identifier       False
reserve_policy no_reserve                       Reserve Policy                   True
lsattr -El hdisk572 :-
pvid           00c3a085229ab91a0000000000000000 Physical volume identifier       False
reserve_policy no_reserve                       Reserve Policy                   True
lsattr -El hdisk1023 :-
pvid           00c3a085229ab91a0000000000000000 Physical volume identifier       False
reserve_policy no_reserve                       Reserve Policy                   True
lsattr -El hdisk1024 :-
pvid           00c3a085229ab91a0000000000000000 Physical volume identifier       False
reserve_policy no_reserve                       Reserve Policy                   True
lsattr -El hdiskpower3 :-
pvid           none               Physical volume identifier                     False
reserve_policy no_reserve         Reserve Policy used to reserve device on open. True
devrsrv -c query -l hdisk2

Device Reservation State Information ================================================== Device Name : hdisk2 Device Open On Current Host? : YES ODM Reservation Policy : NO RESERVE Device Reservation State : SINGLE PATH RESERVE Path Id of Reserved Path : 0

Cause

Generic IBM ODM originally placed single_path reservation and it does not get released when Dell EMC ODMs are installed and paths moved under them.

Solution

"devrsrv -c release -l hdiskXX" will clear reservation which will not return.

Additional Reference: https://www.ibm.com/docs/en/aix/7.2?topic=d-devrsrv-command