[linux-lvm] LVM and hardware device re-ordering?

[AJ Lewis]

On Fri, Apr 30, 2004 at 08:55:32AM -0700, Don Buchholz wrote:
> The one nagging question in my mind is:
> 
>  How resilient is LVM to a sudden renumbering of
>  physical hard disks?
> 
> Assume no disks have actually failed, just that a new disk
> gets added and suddenly all the LVM drives get notched up
> a drive letter. 

It's fine.  Each disk (PV) is labeled with a UUID, which uniquely identifies
it to the system.  'vgscan' identifies this after a new disk is added that
changes your drive numbering.  Most distros run vgscan in the lvm startup
scripts to cope with this on reboot after a hardware addition.  If you're
doing a hot-add, you'll have to run this by hand I think.  OTOH, if your vg
is activated and being used, the renumbering should not affect it at all.
It's only the activation that needs the identifier, and the worst case
scenario is that the activation will fail without a vgscan with a complaint
about a missing PV.

Regards,
-- 
AJ Lewis                                   Voice:  612-638-0500
Red Hat Inc.                               E-Mail: alewis at redhat.com
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Minneapolis, MN 55414

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