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Fedora and LVM

Posted Nov 1, 2012 12:06 UTC (Thu) by Cato (subscriber, #7643)
In reply to: Fedora and LVM by rleigh
Parent article: Fedora and LVM

I think most LVM users don't do much with snapshots, if they even use them, and the snapshot code is much more buggy as a result.

The non-snapshot LVM/DM code is not too bad, though there are some tools issues - e.g. pvmove can corrupt data if it runs out of memory - see http://serverfault.com/a/339899/79266 and http://deranfangvomende.wordpress.com/2009/12/28/a-primer...

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Fedora and LVM

Posted Nov 1, 2012 17:44 UTC (Thu) by nix (subscriber, #2304) [Link]

pvmove uses snapshots internally, so this is just another indication of the general principle that LVM snapshots are dangerous.

Fedora and LVM

Posted Nov 1, 2012 21:32 UTC (Thu) by agk (guest, #23332) [Link]

> pvmove uses snapshots internally

pvmove uses mirrors, not snapshots.

It works by setting up temporary mirrors for the kernel to sync the data between the old and new locations.

Fedora and LVM

Posted Nov 1, 2012 22:29 UTC (Thu) by nix (subscriber, #2304) [Link]

Oh. You're right, of course. (I've only ever encountered one pvmove failure, anyway -- a deadlock -- and it restarted fine on reboot.)