Tux3: the other next-generation filesystem

Posted Dec 3, 2008 7:23 UTC (Wed) by daniel (guest, #3181)
In reply to: Tux3: the other next-generation filesystem by rsidd
Parent article: Tux3: the other next-generation filesystem

Snapshots do not take care of all undelete cases - you might not have taken a snapshot before deleting something important. But I am thinking in terms of using the snapshot mechanism to support undelete, essentially creating an "anonymous snapshot" just for the directory where the delete happened. This could be done without wasting a lot of space by using Tux3's versioned attribute model, which would avoid having to use a full disk block just to remember a single undeleted name.

Tux3: the other next-generation filesystem

Posted Dec 3, 2008 8:05 UTC (Wed) by rsidd (subscriber, #2582) [Link]

I've seen your email exchange with Matt Dillon on tux3 and hammer on the dragonfly lists some time back. Hammer can take snapshots at very fine-grained interval -- say every few minutes -- via a cron job and it is not very expensive (supposedly -- I haven't used it myself, yet). That would be incredibly useful. Undelete doesn't take care of all recovery requirements either -- you may have deleted text in a document that you later want back, for example. With hammer, just look at the snapshot from 2 minutes before you deleted it.

I suppose if you have a filesystem where many bulky files are being altered frequently, this is not a great idea, but you can tune the frequency of the snapshot and pruning (or disable snapshotting entirely, if need be...)