Configure retention and purge a datastore

Set your backup retention policy from the Retention tab, and purge a datastore when needed.

Last updated: May 19, 2026

Retention determines how long your backups are kept. Prune is the operation that removes snapshots that fall outside that policy. Everything is configured from the Cloud-PBS dashboard.

Accessing the retention settings

  1. Open the Cloud-PBS dashboard.
  2. Select the relevant datastore (instance).
  3. Open the Retention tab.

Retention parameters

The retention policy combines several rules. Each one sets a number of snapshots to keep for a given time granularity:

ParameterEffect
Keep lastNumber of most recent snapshots to keep, regardless of their date.
Keep hourlyKeeps one snapshot per hour for the last N hours.
Keep dailyKeeps one snapshot per day for the last N days.
Keep weeklyKeeps one snapshot per week for the last N weeks.
Keep monthlyKeeps one snapshot per month for the last N months.
Keep yearlyKeeps one snapshot per year for the last N years.

A parameter left at zero disables the matching rule.

How the rules combine

A snapshot is kept as soon as at least one rule retains it. A single snapshot can satisfy several rules at once: it may count both as the last snapshot of the day and the last snapshot of the week.

For example, with “daily = 7”, “weekly = 4” and “monthly = 6”, you keep a daily point for the last 7 days, then a weekly point over 4 weeks, then a monthly point over 6 months. The history thins out as you go further back: disk usage stays under control while keeping archive depth.

WARNING

A policy that is too restrictive deletes backups. Check your settings before saving them: snapshots removed by a prune cannot be recovered.

Once the policy is saved, it applies to the following cleanup cycles.

Purging a datastore

Purging a datastore deletes all of its backups. This is useful to start over from a clean datastore, or before decommissioning it.

The action is in the Danger zone of the datastore settings.

  1. Open the relevant datastore, then the Danger zone section.
  2. Click Purge datastore. All backups and their snapshots will be deleted, both on the PBS server and in the Cloud-PBS database.
  3. A confirmation is required: type SUPPRIMER to confirm.

The Free disk space immediately option forces the cleanup: space is reclaimed at once, instead of waiting about 24 hours for the next garbage collection cycle.

CAUTION

Purging a datastore is irreversible. No backup can be recovered afterwards. Only use this action if you are certain you no longer need any of the datastore’s backups.