Kerio Connect is a commercial email/groupware server and MS Exchange alternative that runs on Linux, Mac OSX and Windows. It is a great solution for organizations that require full featured email hosted in house without the licensing costs of MS Exchange.
The built in email backup schedule in Kerio Connect can do full and incremental backups of the server’s entire mail store on a custom schedule. By default, the mailstore backups are stored in a series of 2GB dated zip files. On servers that have large mailstores, this can potentially result hundreds of zips generated by a full backup.