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Date: Tue, 21 Feb 2012 17:07:43 +0000
From: Alasdair G Kergon <agk@redhat.com>
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Subject: Re: [linux-lvm] Duplicate PV's - how does LVM choose which one
	to	use
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To: Stuart D Gathman <stuart@bmsi.com>
Cc: linux-lvm@redhat.com

On Tue, Feb 21, 2012 at 11:49:40AM -0500, Stuart D Gathman wrote:
> But if they are different paths, incrementing seqno won't hurt, both  
> paths will see the change.  And if it is a mirror that failed to start,  
> then the chosen leg is now distinguishable.  Is there a problem with  
> incrementing seqno an extra time at startup when multipath is the normal  
> situation?

If you update some PV-level indicator and only one path sees the update, then
that's exactly a case where you must use neither until the sysadmin decides
which was the right one to use.  And the other case - multipath - well again,
why didn't your multipath software start up and take control?

Alasdair