HPC Data Recovery#

We keep regular data snapshots for all our shared storage systems. This includes the storage of VSC_HOME, VSC_DATA and VSC_SCRATCH in your account as well as VSC_DATA_VO and VSC_SCRATCH_VO in your Virtual Organization.

See also

The documentation on HPC Data Storage has a detailed description of each storage in our clusters.

Storage snapshots keep the state of files and directories at fixed moments in time. We take regular snapshots at varying time intervals depending on their age. The older the snapshots, the less frequent they are. This means that if you accidentally delete or make changes to files in the cluster, you are more likely to recover that data in the same state it was lost the sooner you act.

Storage interval frequency depending on their age#

Snapshots age

Snapshots frequency

Maximum risk of data loss

Less than 3 days

Hourly

1 hour

Between 3 and 7 days

Daily

1 day

Between 1 and 4 weeks

Weekly

1 week

More than 4 weeks

Monthly

1 month

Restoring old files/folders#

Restoring a file or directory from one of the snapshots is relatively easy with the command tool mysnapshots.

First of all you have to change directory cd to the directory that contained (or still contains) the file/directory to be restored. If that parent directory does not exist anymore, you can jump up to the last parent directory that still exists. In the worse case where a lot of data is lost, this location might be the top directory of $VSC_DATA or $VSC_SCRATCH for instance.

$ cd $VSC_DATA/labo
$ ls -l
total 8
-rw-rw-r-- 1 vsc10930 vsc10930 2261  5 nov  2024 job.sh
-rw-rw-r-- 1 vsc10930 vsc10930  907  5 nov  2024 results_dir

The command mysnapshots always works on the snapshots of the current working directory. You can use it without arguments to list the available snapshots for that directory ordered by date/time.

$ mysnapshots
Snapshots of $VSC_DATA/labo:
2025-05-08T17:02:44  2025-05-08T22:02:08  2025-05-09T08:01:56  2025-05-09T13:02:02

The output of the previous command shows the timestamps of the four snapshots with data for the working directory. Now if we want to know which files/directories are available in a specific snapshot, we can execute mysnapshots with the timestamp of that snapshot in the given YYYY-MM-DDTHH:mm:ss format as argument:

$ mysnapshots 2025-05-09T13:02:02
Inventory of $VSC_DATA/labo at 2025-05-09T13:02:02:
job.sh      results_dir   old_data

In this case mysnapshots shows that for the snapshot 2025-05-09T13:02:02 there are three entries available. The entries job.sh and results_dir are already present in the current directory, while the entry old_data is not.

You can restore any of these entries to their previous state at 2025-05-09T13:02:02 by calling mysnapshots with the timestamps of the snapshot and the path to this item as argument. For instance, we can recover the missing entry old_data from this snapshot:

$ mysnapshots 2025-05-09T13:02:02 old_data
Restoring file '$VSC_HOME/labo/old_data' from snapshot at 2025-05-09T13:02:02
Restoration complete
$ ls -l
total 12
-rw-rw-r-- 1 vsc10930 vsc10930 2261  5 nov  2024 job.sh
-rw-rw-r-- 1 vsc10930 vsc10930  907  5 nov  2024 results_dir
-rw-rw-r-- 1 vsc10930 vsc10930   97  9 mei  2025 old_data

Warning

By default, mysnapshots will refuse to overwrite existing files/directories in your working directory. Use the -f option to force the restoration of existing items. Beware that restoring an already existing directory with the -f option will also restore all files and folders within it as they were at that point in time. More recent files will be removed and all updates since then will be lost.

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