Libelle Mail Archive Manual

Setting up backups

Making backups

There are two complimentary ways of doing backups:

1. Use the database's native backup utility.
2. Use the Libelle Mail Archive's database-independent MABackup utility

Native backups

The native backup may be relatively slow since it will back up the entire database and its metadata each time it is run. It may also not produce backups that are suitable for migration to a different database.

Use pg_dump for PostgresQL.

The Libelle Mail Archive backup system

If the Libelle Mail Archive backup system is to be used, it will have been configured as part of the Installation step 4: Downloaded file placement and customisation.

MABackup is designed to provide a fast, incremental backup and to be database-independent. Each time it is run:

• Messages archived since its last run are backed up by writing them into a set of mbox format files.
• The address list is completely backed up to preserve flags settingd and address changes made with the MAUpdate utility.
• A control file that lists increments and the number of messages in each increment is updated.
• The size of each message file is configurable: each time one reaches the configured number of messages a new file is started. The address file is very much smaller so it is never split up.

MAUpdate has the ability to remove unwanted messages, e.g. spam, and associated addresses from the archive. To avoid keeping backups of the unwanted messages and addresses, MAUpdate notifies MABackup that deletions have taken place by making a note in the database. This causes MABackup's next run to delete all existing increments and do a complete backup. After this it reverts to incremental operation. The full backup is about 10-20% slower than the equivalent native database backup.

It is the archive owner's responsibility to organise the storage of offline copies of either type of backup.

Incremental backups are much faster than either native database backups or a full backup with MABackup. Representative performance details are given here.

Restoring backups

Native backups

See your database manual for details of how to restore native database backups.

Use pg_restore for PostgresQL.

The Libelle Mail Archive backup system

Restoring from this type of backup is a four step process:

1. Create the database as described in Installation step 5: Create the database.
2. Bring the backup files back online. You need all increments, addresses and the control file.
3. Use MALoader to load each incremental backup file in turn. This process is described in step 7: Loading manually archived mail.
4. Use MABackup's -r option to restore the manually recorded information in address records.