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Backups and Snapshots


Backups

Tape backups of the data storage are performed for the purposes of disaster recovery and do not provide the ability to recover old or lost files. However, we utilise GPFS snapshots, and if the file exists on an overnight snapshot, you can recover them as shown in the snapshots section

What is backed up:

  • User home directories /data/home
  • Shared project storage /data/

What is NOT backed up

  • Scratch Space /data/scratch
  • auto deleting scratch space/data/autoScratch

The backup schedule consists of daily incremental backups which are retained for a month. This is currently handled by Spectrum Protect (previously TSM) to build a full backup. The tapes are kept geographically separate to our cluster.


Snapshots

Snapshots are taken daily and are kept for a couple of days, they hold a copy of the entire storage at the point they were taken. All files exist in the snapshots with exactly the same permissions as they did in the original, which means you can recover files from snapshots yourself.

Snapshot Structure

Snapshots can be found under /data2/.snapshots for group file shares and home directories; Scratch snapshots can be found under /data1/.snapshots. These locations contain a dated directory for each available snapshot.

These directories are named by date (any additional ones are there for administration purposes, such as taking tape backups). Below these directories is the same directory structure as the rest of the GPFS file store. Hence home directories are under /data2/.snapshots/YYYY-M-D/home/abc123 etc.

These directories are read-only; they can not be changed.

A full list of available snapshots can be gathered with mmlssnapshot home for group shares and home directories and mmlssnapshot gpfsWork for scratch and autoScratch, for example:

$ mmlssnapshot home
Snapshots in file system home:
Directory                SnapId    Status  Created                   Fileset
2018-6-20                1344      Valid   Wed Jun 20 23:02:22 2018
2018-6-21                1346      Valid   Thu Jun 21 23:00:02 2018
2018-6-22                1348      Valid   Fri Jun 22 23:00:05 2018
2018-6-23                1350      Valid   Sat Jun 23 23:00:02 2018
2018-6-24                1352      Valid   Sun Jun 24 23:00:02 2018
2018-6-25                1354      Valid   Mon Jun 25 23:00:01 2018
2018-6-26                1356      Valid   Tue Jun 26 23:00:02 2018

Recovering files from snapshots

To recover a file from the snapshot simply copy it somewhere outside the .snapshots directory.

cp /data2/.snapshots/<date>/home/abc123/lost_file /data/home/abc123/recovered_data/