Zimbra performs a “hot” backup (no downtime). By default, two full backups are performed each week. With daily incremental backup (about 10% size). Backups are retained for 2 weeks. As a guide, reserve x2.5 total mailstore size for backup storage (plan for growth!). Both users and administrators can restore mailboxes from backups easily. It is a simple point’n click action. Backups can be restored to point in time, to a new mailbox or restore to the active mailbox.