Fundamentals: Pools

The Pool resource defines the set of storage Volumes (tapes or files) to be used by Bacula to write the data. It permits to configure the data stored on disk volumes, tapes or cloud storage. By configuring different Pools, you can determine which set of Volumes (media) receives the backup data. This permits, for example, to store all full backup data on one set of Volumes into a specific Pool, and all incremental backups on another set of Volumes belonging to another Pool. Alternatively, you could assign a different set of Volumes to each machine that you backup. Another important aspect of a Pool is that it contains the default attributes (Maximum Jobs, Retention Period, Recycle flag, etc.) that will be given to a Volume when it is created. The Pool resource is a key part of a backup strategy as it permits to group data under the same backup policy under the same Pool.

See the Pool Resource chapter to know more about the Pools.

See the Volumes chapter to know more about Volumes.

As mentioned, Pools in Bacula are a way to manage volumes and to manage collections of similar volumes.

Note

You might have either different requirements or even no requirement to separate volumes into several pools.

The examples of Pools:

Pools: “short-term” and “long-term” to handle short and long retention periods.
Pools: “big-customer” and “usual-customers” to keep all the backup jobs from your client “Big Customer” in a specific pool while putting all “usual” customers into another one.
Pools: “r-and-d” and “accounting” to keep R&D backups together and the Accounting ones in another pool, separated from each other.

There can be many reasons to use or not use several Pools. Bacula configuration gives the Backup Administrator the ability to match the defined requirements.

Due to how Bacula manages Volume retention periods, the jobs put into the same pool should have the same retention periods.

See more details on how to convert an enterprise backup policy into a Bacula backup policy here.

Pool Types

Bacula has different kinds of pools:

Scratch
Backup
Recycle

A Scratch pool contains volumes that may be with any pool. If no volumes are available, Bacula will look in the Scratch pool and move/supply a volume to that pool.

A Backup pool contains volumes intended to keep data from backups for a defined retention period. It can also include Recycled or Purged volumes, i. e. Volumes that are eligible to be overwritten.

A Recycle pool contains volumes that have been used in a Backup Pool after the purge process freed them

The Bacula configuration allows the Administrator to attach a Scratch Pool and a Recycle Pool to a Backup pool.