> There about 20 virtual domains with more than 1000 mailboxes. I am not
> sure the imapsync workable for me or not, But i will do some test with
> it.

*cough* That would be less than fun to back up on a per account basis.

> And all the data should be backuped. Because of all of them are in a
> production server. I could not let any letter missed,

I pose a question to you. What do you want the backup to protect against / provide? Are you wanting to protect against hardware failure? Or are you trying to protect against some sort of data corruption (presuming good hardware) such as someone editing a file (not so pertinent for email as word documents) with multiple versions? How important is it to be able to restore a message after a user deletes it?

> I think a incremental backup is the best solution.

Possibly. I think knowing what you are wanting the backup to protect against will better answer this question.



Grant. . . .