Perhaps the problem is due to the bad VG still being varied on, and the fact that both disks have the same pvid. When you reboot, the bad disk will go to Defined state and the VG will varyon using the DR disk if it is Available.
To avoid reboot, after umount -f, you'd need to varyoffvg and then delete the bad disk (rmdev -l). Now lspv should only list the DR disk as a member of the VG. varyonvg should then activate the VG using the DR disk. Then fsck and mount.
Original Message:
Sent: Fri June 30, 2023 01:50 AM
From: Glenn Robinson
Subject: Accessing primary and DR copies of an iSCSI LUN
Yes, I did try to force the unmount.
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Glenn Robinson
Original Message:
Sent: Fri June 30, 2023 01:19 AM
From: CHRISTOPHER WICKREMASINGHE
Subject: Accessing primary and DR copies of an iSCSI LUN
Hi Glenn
Did you try umount -f to force-unmount the file system?
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Chris Wickremasinghe
IBM
Original Message:
Sent: Thu June 29, 2023 04:39 PM
From: Glenn Robinson
Subject: Accessing primary and DR copies of an iSCSI LUN
Yes, the NAS is doing the replication.
i did think about using importvg/exportvg but i"d still have the same issue if the primary iSCS LUN failed. I wouldn't be able to unmount the FS from the primary iSCSI LUN's LV therefore I can't mount it over the DR iSCSI LUN's LV.
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Glenn Robinson
Original Message:
Sent: Thu June 29, 2023 03:37 PM
From: Cesar Daniel Delgado Ponce
Subject: Accessing primary and DR copies of an iSCSI LUN
Hi Glen.
Question: is the replication executed at storage subystem level ?? Or OS level ??
I would do the replica using the storage subsystem facilities, with the VG in offline mode, then in testing time i would varyonvg the VG. i think some problems might arise when mounting the FS.
HTH
Original Message:
Sent: 6/29/2023 2:48:00 PM
From: Glenn Robinson
Subject: Accessing primary and DR copies of an iSCSI LUN
I'm after some thoughts on the following scenario.
Customer has AIX 7.2 running in primary and DR locations.
They access an iSCSI LUN from a local (primary) NAS server.
They are installing a second NAS server at another (DR) location.
A replicated (DR) copy of the LUN from the primary NAS will also be available to AIX using iSCSI.
So, if the primary NAS fails then I need to mount the DR LUN. The NAS will make this copy read/write if the primary is not available.
I've had issues before when the primary NAS has failed where I am unable to unmount the file system from the failed iSCSI hdisk unless I reboot AIX.
Ideally, if the primary iSCSI hdisk is no longer available I would mount the file system over the VG on the secondary iSCSI hdisk. If I can't unmount the file system then I'm unable to do this.
Anyone else had a situation like this with a primary and replicated secondary iSCSI volume and how to handle a failure?
I realise I could use AIX to do the replication but if the production AIX system fails I would need to access the iSCSI volume on the DR AIX system.
All useful comments and suggestionwelcome.
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Glenn Robinson
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