It is possible to configure MailArchiva to automatically delete or retain emails residing in the archive after a specific retention period, based on a set of retention rules. A retention rule specifies the length of time and conditions under which a set of emails is either retained or deleted. A retention rule consists of an action, a time period and a filter. The action can be either “hold” or “delete”. The time period is specified in number of days since the email was sent. The filter is a search query that defines the set of emails to which the rule applies.
Extreme caution should be applied when defining a rule's filter clause, as an incorrectly specified filter can result in desired emails being deleted en bulk. Thus, before defining a rule, it is strongly advised to perform equivalent search queries in the Search interface in order to verify and test that the filter will indeed match the targeted results. Ordering is significant - a preceding rule will always be processed before a subsequent one. For example, a matching hold action will apply irrespective of the matching delete actions below it. If none of the defined retention rules match, the default rule applies. In the default rule, one can specify the number days after which time the emails will be deleted from the store. The purge job is executed 15 minutes after the server starts, and every hour thereafter. Thus, the maximum time to wait before a newly defined retention rule starts being effected is one hour.
If an email is deleted, depending on the format of the volume in which the emails reside, the disk space may not be immediately freed. Emails residing in a V2 volume will be marked as deleted. The space will only be freed when the volume is compacted (i.e. its archive files are rewritten). To manually compact a volume, click on the Compact button in Configuration->Volumes next to the volume in question. The compact process rewrites each of the archive files in the volume. When it does so, rewritten archive files will no longer contain the deleted info. It is also possible to enable auto volume compaction, though this time is not recommended. Emails residing in a V1 or V3 volume will be erased immediately, and space will be freed instantaneously. To create a V3 volume, set the new volume format to V3 in Configuration->General->Archive, close the existing volume and create a new one in Configuration->Volumes.
Found this information useful? Visit mailarchiva.com to learn more about MailArchiva.