Hi, Christian Völker wrote on 2011-07-12 00:17:57 +0200 [Re: [BackupPC-users] My Solution for "Off-Site"]: > On 11/07/2011 21:58, Les Mikesell wrote: > > The way my 'take a disk off RAID1' works is that there are 3 spare > > disks, with at least one always offsite in the rotation [...] > > I'm aware of the rotation there- it's just the same and only a question > on levels you do it. You have three disks and swap them at some time. I > take snapshots instead. In both cases it can happen a filesystem error > gets copied over, too.
so, you're saying that you don't trust your file system, but you trust LVM to keep 4 snapshots accurate for up to four weeks? I think I understand Les' point (if he's making it) that a hardware-based "don't do anything" approach is more reliable than a software-based "accumulate the information needed to undo all my changes". But I also understand your point of "as long as it works, it gives me three previous states to go back to". > I think I might move it to the garage, though :) I hope your data is well enough protected against theft in your garage. > > [...] to understand how you can drbd to the live partition while keeping > > snapshots of old copies. I wouldn't have expected that to work. Are > > they really layered correctly so the lvm copy-on-write business works? Why shouldn't it work? An LVM LV is just a block device. Why should the snapshotting be in any way dependent on the type of data you have on top? > Yes, this works absolutely fine. [...] Taking a snapshot of the LVM volume > doesn't affect the drbd device at all. I'm just wondering whether you're unmounting the pool FS before the snapshot, or if you're relying on it to be in a consistent state by itself. How much testing have you done? > The only thing I have to evaluate is to have the proper size of the > snapshot. Which, in itself, doesn't sound practical. Effectively, you are estimating how much new data your backups for a week (or four weeks?) will contain. I just hope you don't decide to implement a BackupPC fork with deduplication implemented through LVM snapshots ;-). Regards, Holger ------------------------------------------------------------------------------ All of the data generated in your IT infrastructure is seriously valuable. Why? It contains a definitive record of application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-d2d-c2 _______________________________________________ BackupPC-users mailing list BackupPC-users@lists.sourceforge.net List: https://lists.sourceforge.net/lists/listinfo/backuppc-users Wiki: http://backuppc.wiki.sourceforge.net Project: http://backuppc.sourceforge.net/