On Tuesday, January 11, 2011 15:33:38 Ivan LabÃth wrote:
> On 01/11/11 15:19, Hubert Kario wrote:
> > On Tuesday, January 11, 2011 14:54:38 Ivan LabÃth wrote:
> >> On 01/10/11 14:36, Hubert Kario wrote:
> >>> On Monday 10 of January 2011 14:25:32 Carl Cook wrote:
> >>>> Here is my proposed cron:
> >>>>
> >>>> btrfs subvolume snapshot hex:///home
> >>>> /media/backups/snapshots/hex-{DATE}
> >>>>
> >>>> rsync --archive --hard-links --delete-during --delete-excluded
> >>>> --inplace --numeric-ids -e ssh
> >>>> --exclude-from=/media/backups/exclude-hex hex:///home
> >>>> /media/backups/hex
> >>>>
> >>>> btrfs subvolume snapshot droog:///home
> >>>> /media/backups/snapshots/droog-{DATE}
> >>>>
> >>>> rsync --archive --hard-links --delete-during --delete-excluded
> >>>> --inplace --numeric-ids -e ssh
> >>>> --exclude-from=/media/backups/exclude-droog droog:///home
> >>>> /media/backups/droog
> >>>>
> >>>> Comments? Criticisms?
> >>>
> >>> This will make the dates associated with snapshots offset by how often
> >>> cron is run.
> >>>
> >>> In other words, if you run above script daily you will have data from
> >>> 2011.01.01 in the hex-2011.01.02 directory.
> >>>
> >>> I do save the current date, do a LVM snapshot on the source, rsync
> >>> --inplace data over and do a local snapshot naming the folder using the
> >>> saved date. This way the date in the name of backup directory is exact
> >>> to about a second.
> >>
> >> If you are mounting a LVM snapshot of an already mounted filesystem,
> >> would you be willing verify that it is really a snapshot that is
> >> mounted?
> >>
> >> e.g. touch /mnt/live/its_alive && ls /mnt/snapshot/
> >>
> >> I am nearly willing to bet it is not a snapshot.
> >
> > well, by "LVM snapshot on the source" I meant:
> > 1. do lvcreate --snapshot
> > 2. mount newly created volume
> > 3. use the new directory as the base for rsync
> > 4. arrange umount and destruction of the snapshot after rsync completes
> > (no matter if it was successful)
> >
> > and this will in fact not make the "its_alive" visible in /mnt/snapshot
> >
> > You have to use this procedure if you use LVM snapshots for backup no
> > matter to where do you copy data. That's why I shortened it to a single
> > point -- it's not the part that is important from btrfs perspective.
> >
> > Regards.
>
> The point I was trying to make is: it does not work with btrfs.
> Try the above with a btrfs and you will be surprised.
> If the source volume uses another filesystem, it should work properly.
>
> regards,
> ivan
Yes, you are right, but I don't see a point in using LVM snapshots with btrfs,
after all the ability to snapshot it on fs level is one of its defining
features...
--
Hubert Kario
QBS - Quality Business Software
02-656 Warszawa, ul. KsawerÃw 30/85
tel. +48 (22) 646-61-51, 646-74-24
www.qbs.com.pl
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