Raul, did you ever get a reply to this? I have been doing HSM processes, where I try to move 30% of the e-mail to another volume, only to find a very small fraction of that space actually freed up. Guess I'll have to keep searching...
edit: I discovered my problem. We disabled incremental backups, and were relying on a nightly full backup only. incremental backups clean /opt/zimbra/redolog/archive ...
