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

[Alasdair G Kergon]

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