Snapshots and recovery
A snapshot is a technical mechanism: a read-only, point-in-time copy of a filesystem that lets you recover an earlier version of a file. It is not the same thing as a backup in the broader, institutional sense — a snapshot lives on the same storage system as the data it snapshots, so it protects against accidental deletion or a bad edit, not against a failure of that storage system itself.
Important This page describes what was directly observed on the storage system at the time it was reviewed. It is not a statement of an institutional backup guarantee. For data-protection responsibilities and requirements, see Institutional responsibility.
What exists on home#
At the time this page was reviewed, /home/<KU-ID> had three snapshot tiers, read-only:
| Tier | Frequency | Depth observed |
|---|---|---|
57-Research-hourly-7D | Hourly | 7 days (168 snapshots) |
58-Research-daily-30D | Daily | 30 days |
59-Research-weekly-104W | Weekly | Up to 104 weeks |
These are visible under /home/<KU-ID>/.snapshot/, and are strictly read-only — writing into a snapshot directory fails.
Note This describes what was observed on the review date above. Snapshot configuration is an infrastructure setting, not a published guarantee, and could change without necessarily being reflected here immediately. If a specific recovery matters to you, confirm through Getting help rather than assuming.
What was NOT observed on project storage#
/projects/.snapshot and per-project .snapshot directories were checked directly and do not exist. This means no equivalent recovery mechanism was found for /projects/<project>/ at the time of review — not that project data is confirmed to be unprotected. The protection status of project storage could not be established from read-only inspection, and should not be assumed either way.
Warning Do not assume /projects/<project>/ has the same recovery options as home. If a recoverable copy of project data matters, ask through Getting help rather than relying on an assumption either way.
Recovering a file from home#
If you accidentally deleted or overwrote a file in your home directory, you can typically retrieve an earlier version yourself, since the snapshots are ordinary read-only directories:
# list available hourly snapshots
ls /home/<KU-ID>/.snapshot/
# look inside one for your file
ls /home/<KU-ID>/.snapshot/57-Research-hourly-7D-<date>_<time>/
# copy the earlier version back to your live home directory
cp /home/<KU-ID>/.snapshot/57-Research-hourly-7D-<date>_<time>/path/to/file ~/path/to/filePick the most recent snapshot that still has the version you want — start with the hourly tier and fall back to daily or weekly if the file is older than 7 days.
Warning Copy the file out of the snapshot to its normal location. Never try to edit or delete anything inside .snapshot itself — it is read-only and not meant to be worked in directly.
When to ask for help instead#
Go to Getting help when:
- The file you need is not in
/home(see the section above on project storage) - You can't find the version you need in any available snapshot
- You're not confident about which version to restore
- The data matters enough that you'd rather not guess