Backups

Backups? Backups!¶

Currently, HPC@UCD offers backups for Hive. We automatically backup home directories once a day. PI/group directory backups can be purchased.

What software is used?¶

HPC@UCD has written a custom backup system based around the Proxmox Backup Server (PBS).

How to restore files or directories¶

Restore a file from your home directory¶

$ cd ~
$ /quobyte/pbs/bin/restore.sh

You will see a list of snapshots. Pick the one you want to restore the file from (up/down arrows), then press enter. The snapshot you selected will be automatically mounted to a random directory, which is printed (for example /home/omen/restore-fCnNXIUr).

Please chose a snapshot to restore from.

┌─────────────────┤ Please chose a snapshot to restore from. ├─────────────────┐
│ Snapshots, newest to oldest:                                                 │
│                                                                              │
│                      1  host/omen/2025-03-18T07:13:02Z                       │
│                      2  host/omen/2025-03-17T22:51:54Z                       │
│                      3  host/omen/2025-03-16T07:16:32Z                       │
│                      4  host/omen/2025-03-15T07:15:07Z                       │
│                      5  host/omen/2025-03-14T07:00:04Z                       │
│                      6  host/omen/2025-03-13T07:05:46Z                       │
│                      7  host/omen/2025-03-12T07:17:56Z                       │
│                      8  host/omen/2025-03-09T08:10:37Z                       │
│                      9  host/omen/2025-03-02T08:17:44Z                       │
│                      10 host/omen/2025-02-23T08:08:58Z                       │
│                                                                              │
│                     <Ok>                         <Cancel>                    │
│                                                                              │
└──────────────────────────────────────────────────────────────────────────────┘

You can open another connection to Hive, then cd into that directory (cd /home/omen/restore-fCnNXIUr), find the file(s) or directory(s) you need to restore, then cp to your desired location.

Snapshot selected.

┌─omen@login1.hive: ~
└─0 $ /quobyte/pbs/bin/restore.sh
Loading snapshots, done.
Mounting chosen snapshot: host/omen/2025-03-18T07:13:02Z to /home/omen/restore-zCgS0D1Z
Encryption key file: '"/quobyte/pbs/home/omen.json"'
Encryption key fingerprint: '21:96:a0:ec:62:62:ae:34'
FUSE library version: 3.14.0

Backups mounted on /home/omen/restore-zCgS0D1Z

Please open another shell and copy any file(s)/directory(s) you need to restore.

It will remain mounted for 1 hour, then automatically unmount.
You can issue Control-c to unmount earlier.

Note, this backup mount (/home/omen/restore-fCnNXIUr in this example) will automatically unmount in 1 hour. Any shells that have cd'd into this directory will remain functional until you close them (or cd out). You can force the directory to umount earlier by pressing Control-c in window where you ran the restore program.

Restore a file from your group directory¶

Restoring files from your group directory is similar to restoring files in your home directory. There are only two differences. First, start in the PI group directory:

$ cd /quobyte/*PI*grp/
$ /quobyte/pbs/bin/restore.sh

Second, the temporary directory will be created in /quobyte/*PI*grp/.

Home Directories¶

Hive¶

All of Hive's home directories have a quota of 20 GB and all backed up automatically every night. As of March 2025, the snapshot keep schedule is listed below, but this is subject to revision as the backup space fills. Individual files and/or directories can be restored by each user.

Snapshot type	Keep count
daily	7
weekly	5
monthly	12
yearly	2

Group directories¶

Rates¶

Group directory backups are available by request on Hive. The current rates are posted on https://hpc.ucdavis.edu/rates under Rates for Hive -> Cost of Backup/Archival (snapshot copy) Storage.

How do I purchase backups for my group directory?¶

You can purchase backups for your storage by emailing HPC@UCD help and including:

The full path to the PI group storage you need backed up.
The amount of storage you would like to purchase.
The list of contacts (email addresses) that are responsible for monitoring the backup status.
The number and type of snapshots you would like.

Please see the How much backup space do I need? section if you have questions about how much backup space to purchase.

What is backed up?¶

The only data that is backed up is the data that resides within the BACKED-UP/ directory at the top level of the PI share. NO OTHER DATA IS BACKED UP. If you have questions about what is being backed up, you should try a test restore.

Who monitors the backups?¶

You, the PI, or a designated list of email addresses. HPC@UCD does NOT, and we cannot emphasize this enough, does NOT monitor the individual backups. It is up to you to monitor those and open a ticket if you see any issues.

How much backup space do I need?¶

This is a surprisingly complex question and depends on how much data you are backing up, how much that data changes (churn), and the total number of snapshots you keep. PBS only stores a single copy of each unique data chunk, so unchanging data is only stored a single time. The short version is you need approximately (initial quantity * snapshots) + (churn * snapshots).

Quantity of Data	Data Churn	Snapshots	Total Required Space
1 TB	0 Bytes per day	Any	1 TB
1 TB	1 TB per day	last=1	1 TB
1 TB	1 TB per day	daily=7	7 TB
1 TB	1 TB per day	daily=7, weekly=4, monthly=6	17 TB
1 TB	100 GB per day	daily=7, weekly=4, monthly=6	2.7 TB

What happens when my backups exceed my purchased space?¶

An error will be sent the email address(es) you designated to monitor your backups.

Purchased quota exceeded example message

!!!!!!!!!! ERROR !!!!!!!!!!

Backup quota exceeded, backed up data is greater than purchased quota.

Please see https://docs.hpc.ucdavis.edu/backups for information about
purchasing more space, or contact HPC@UCD to adjust your retention policy,
which is currently: --keep-daily=14 --keep-weekly=5 --keep-monthly=2 **EXAMPLE ONLY**

BACKUP CANCELLED!

At this point you have 4 options:

Contacting HPC@UCD support and purchasing additional backup storage space.
Backup less data by reducing the amount of data in your BACKED-UP/ directory. This will require old data to age out before new data can be backed up.
Ignore it. Eventually old data should age out and new data should be able to be backed up again.
Reduce the number of snapshots you keep by contacting HPC@UCD support. For example, if you keep 6 monthly, you could reduce that to 3. This will age-out (delete) the data greater than 3 months, freeing up space for new data.

How often are backups taken?¶

The backup system starts at midnight every night and works its way through a randomly shuffled list of PI areas it needs to backup. The actual start time of your backup depends on how much data needs to be backed up before you, and your order in the shuffle.

What types of snapshots are available?¶

PBS offers the following types of snapshots:

last: Keep the last N snapshots.
daily: Keep the last N daily snapshots.
weekly: Keep the last N weekly snapshots.
monthly: Keep the last N monthly snapshots.
yearly: Keep the last N annual snapshots.

There is a simulator to test various settings.

Note, last=1 means a single copy (the latest) will be retained of each file. This is effectively a "snapshot" copy for disaster recovery purposes only.

How many snapshots do I need?¶

Unfortunately, we cannot help with this. It depends on your contractual obligations, and/or how far back in time you need to be able to retrieve old versions, or deleted, files.

Are my backups encrypted?¶

Yes, all backups are encrypted with a key that is unique to every PI group. This key is protected with normal Linux file-system permissions, and only users in the PI group will be able to even read it to restore data.

Who can restore files?¶

Anyone in the PI group can initiate a restore, however, you will only be able to restore files you had read access to at the time the file was backed up. This means that files/directories with permissions that prevent PI access on disk also prevent PI restore. If you, as a PI, run into this situation, please contact HPC@UCD support by HPC@UCD support with the following information, and we can restore the files for you.

The cluster.
The full path to the files/directories you need restored.
The full path to the place you would like them restored to.

How do I make changes to my quota, snapshots or monitoring designee list?¶

Changes can be made by contacting HPC@UCD support.

How often are backups run?¶

Backups are run once a day, starting just after midnight.

FAQ¶

Where is the backup server located?¶

The backup server is located in the Academic Surge building, so it is outside the Campus Data Center, but still on-campus. This may be important for certain grant requirements.

What happens if the backup server is also destroyed?¶

At this point, the data would be permanently lost. HPC@UCD does not replicate the backup data to any off-site location(s).