[linux-lvm] removing an origin from under snapshots

[linux-lvm] removing an origin from under snapshots

[Brian J. Murrell]

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I am fairly sure LVM does not currently allow this, but what I would
like to do is create one or more snapshots of an origin, work within the
snapshot(s) and then remove the origin.

Understanding a bit about how LVM works, I can understand some of the
problems with this.

      * All snapshot volumes would need to be (expanded to the) same
        size as the origin.
      * In the case of multiple snapshots, snapshots n+1 would need to
        have the blocks it shares with the origin copied to it.

Why would I want to do this you might ask?

Let's say I have a Fedora Core 5 system in /dev/vg00/{root,usr,var}.  I
want to upgrade with the safety of having somewhere to very quickly and
easily fall back to if it goes horribly wrong.  So I make snapshots of
those root, usr, and var volumes, mount them (or reboot from them even)
and try the upgrade.  If and when I'm happy with them I have no use for
the original root, usr and var and would like to collapse them, turning
my snaphots of those volumes into bona fide logical volumes, which I can
then take snapshots of at some time in the future.

Thots?

b.

-- 
My other computer is your Microsoft Windows server.

Brian J. Murrell

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