(please note that we just started to roll out this feature in 2021-04 and your /work directory may not yet allow this!)

Imagine, you accidentally deleted a few files in your /work directory and would like to restore these.

If this happened just recently and the files have been present in your /work directory for some time, chances are quite high, that the storage servers in the background created a read-only snapshot of your data and you can simply copy these files back. To do so, please investigate the “hidden” directory ~/.zfs/snapshot!

For example, imagine you deleted the project directory ~/projects/phd by accident. You can then go into said directory by issuing cd ~/.zfs/snapshot and check what directories there are via ls -l:

total 0
drwxrwxrwx 1 root root 0 Apr  7 08:53 autosnap_2021-04-07_01:00:08_daily
drwxrwxrwx 1 root root 0 Apr  7 08:53 autosnap_2021-04-07_03:00:07_hourly
drwxrwxrwx 1 root root 0 Apr  7 08:53 autosnap_2021-04-07_04:30:07_hourly
drwxrwxrwx 1 root root 0 Apr  7 08:53 autosnap_2021-04-07_06:00:07_hourly

In each of these directories, you will find your whole /work directory how it looked like when the snapshot was taken (time stamp in the directory name).

You can look everywhere in there and simply copy any file you want to have back into your current /work, e.g. if you decided you want to have the most recent state recovered, you could simply use cp -a autosnap_2021-04-07_06:00:07_hourly/projects/phd ~/projects/phd.

A few notes of caution:

  • Files you just created and deleted again are most likely not present in any snapshot as these are only taken every few hours!
  • Snapshots will be renamed or removed periodically as they require space to record any changes between the states of the file system when the snapshot was taken and the current one. Thus, if you want to act, act early!
  • If these snapshots are too recent and your accident happened some time back, please speak send an email to atlas_admin@aei.mpg.de as soon as possible, as we may have those files still on a backup machine you cannot access. But as backup space is also limited they are not kept indefinitely, thus please act fast!