> > I recommend making it an LVM physical volume and creating a volume group on > top of it. Create a logical volume the exact size of the volume you are > backing up, then use dd to copy it for the first time (boot from a CD, if > necessary, so the source volume isn't mounted). Then create an LVM > snapshot. > > For each backup cycle (in a script called from cron), mount it and use > rsync to only change what needs changing, then unmount it and create an LVM > snapshot. Create the snapshots with names that include the date. To avoid > running out of space, you'll probably want to cull older snapshots from > time to time. For example, you might back up nightly, but you only want to > keep the last three days, the first of the month for a year, and the first > of the year from the previous year. You can automate this in the backup > script as well. > > You should also create a script that will mount the available backups > (i.e. LVM snapshots) readonly in well-named directories (i.e. including the > backup date), and another to unmount them all. >
I did something like that for a while, but the mount time to recognize all of the LVM internal pointers for the snapshots was extreme (1/2 hour!). Better to use rsync with the --link-dest= option as in http://blog.interlinked.org/tutorials/rsync_time_machine.html. Stuart
