Lars Ellenberg wrote: > On Sun, Mar 09, 2008 at 11:05:45PM +0100, Bas van Schaik wrote: > >> Hi all, >> >> When I started to use LVM snapshots, I presumed that it was easy to >> restore a system to such a snapshot. As far as I can see now, this >> presumption was incorrect... People on the internet write that I should >> dump the whole snapshot using dd and then write it over the original >> volume. This actually implies that I need another device with at least >> the size of the original volume available to dump to. In my situation, >> this means that I need about 2 TB free space to recover this snapshot! >> >> Isn't there a more sophisticated way to restore the snapshot than just >> dumping it? >> 1) create snapshot of /dev/myvolumegroup/myvolume to >> /dev/myvolumegroup/mysnapshot >> 2) dd if=/dev/myvolumegroup/mysnapshot of=/tmp/mysnapshot.dd >> 3) lvremove /dev/myvolumegroup/mysnapshot >> 4) dd if=/tmp/mysnapshot.dd of=/dev/myvolumegroup/myvolume >> > > you got (size-of-your-volume) free space in /tmp? > pretty large /tmp, or pretty small volume, I guess. > > >> Something like: >> 1) lvrevert /dev/myvolumegroup/mysnapshot /dev/myvolumegroup/myvolume >> >> I'd like to hear your thoughts on this, because I think it should be >> fairly easy to restore a COW snapshot. Or am I wrong and missing something? >> > > you may want to investigate the status of > http://fedoraproject.org/wiki/StatelessLinux/CachedClient > were it says "The LVM and device-mapper code to allow merging is > awaiting upstream review." > Interesting project, interesting information, but it was last updated 2007-10-19. I'll try Googling for a more recent status, if that is available... > or you can try, at your own risk, the hack below. > > (... lots of excellent details ...) Sounds very plausible, but there are some risks involved here ;). Thanks anyhow, I'll really consider using your perl script when the situation gets critical here... -- Bas _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
