On 12/07/2011 01:05, Holger Parplies wrote: > > 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". Take it as you like. I never said I don't trust my filesystem. At least you have to trust *something* or you'll end up in endless layers of security.
We both have the possibility to roll-back to a point some weeks ago. If LVM doesn't work as expected *or* Less disks getting broken during the swap- it's just the same. > 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? You can perform tests multiple times- every time they are fine but in case of emergency something else fails you haven't thought of previously. Meaning: There's no point in testing if a not properly closed filesystem is able to recover as you can't forsee it in any case. I'm using ext3 with data=journal, so it should work fine even without proper unmounting. >> 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 have to estimate how much data changes on the volume for a weeks time, yes. Then I take a snapshot. And another week. So it's a one week estimate. And why should this be an issue? The secondary it a 2TB disk while the original is around 1TB. So the amount of data changing within a four weeks time frame can be 100%. This is fine. Although from monitoring it the change rate per week is far below 100GB.... Greetings Christian ------------------------------------------------------------------------------ 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/
