Standard Backup Method
A full backup process backs up all the information needed to restore mailboxes, including the LDAP directory server, database, index directory, and message directory for each mailbox.
When backing up shared messages, the backup process looks to see whether a file representing a message already exists in the backup. If it does, it flags this object as such and does not copy its content again.
An incremental backup process backs up the LDAP data and gathers all the redo logs written since the last incremental backup.
If the incremental backup process finds no previous full backup for a mailbox, a full backup is performed on that mailbox.
Incremental backups move the redo logs to the backup directory.
The redo logs are a journal of every activity that has taken place. They contain a full copy of all messages delivered, as well as metadata such as tags, contacts, and conversations
These backup files can be used to restore the complete mailbox server or individual mailboxes so that account and message data is completely restored.