Cache and Pruning

The Cloud Plugin write the backup data in a local cache before the data is sent to the Cloud.

It is possible to keep the data in the local cache for some time, or to delete it as soon as the data is stored in the remote cloud.

The Cloud Cache is treated much like a normal Disk based backup, so that when configuring Cloud backups, the administrator should take care to set “Archive Device” in the Device resource to a directory where he/she would normally store data backed up to disk. Obviously, unless the local cache is configured to be pruned/truncated automatically, the Archive Device file system will continue to fill.

The retention of Cloud volumes in the local Cache is controlled per Volume with the new “CacheRetention” Volume attribute. The default value is 0, meaning that the pruning of Cloud Cache Volumes is disabled. The new “CacheRetention” attribute for Cloud Volumes is configured as a Directive in a Pool and is inherited by Cloud Volumes created in this Pool just as with other inherited attributes for regular disk based Pools and Volumes.

The “CacheRetention” value for a volume may be modified with the bconsole update command.

See Bconsole Cloud Commands.

Note

The Cloud Cache will be deleted using the “cloud prune” bconsole command. This command will only delete the part files from the local cache when the CacheRetention is expired.

Cache Pruning and Truncation

These are two different approaches to use to delete part files from the local cache.

When using TruncateCache = AfterUpload or TruncateCache = AtAtEndOfJob, the part files will be deleted from the local cache without checking the CacheRetention value.

To use local cache retention, it is required to configure Truncate Cache = No in the Cloud resource.