[linux-lvm] Duplicate PV's - how does LVM choose which one to use

[Stuart D Gathman]

Long ago, Nostradamus foresaw that on 02/21/2012 11:43 AM, Alasdair G 
Kergon would write:
> On Tue, Feb 21, 2012 at 10:35:03AM -0600, Ray Morris wrote:
>> Perhaps when duplicates are found the seqno should be incremented
>> so it DOES use the same one next time, and generate a warning
>> indicating which one is out of date?
> Wouldn't be possible - it can't distinguish between them (or we'd not
> be in this situation).
>
> If they have the same UUID it assumes they are different paths to the same
> device and picks one of them to use.
>
> But there are other cases (like hardware snapshot, mirror that failed to
> start up first) where it's better to stop and force the sysadmin to fix
> things.
>
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?