I am performing a migration from a debian32 to an ubuntu64 6.0.8 oss.

I decided to give a try to zmztozmig, since I saw in blog posts and elsewhere as official zimbra tool to move a mailbox.

I ran it on a big one, and after it said everything was successful I gave a quick comparison between the two installations: on the old install the account was 4.2G, on the new one 3.3! That's a considerable difference!

I have to say that on the move, the filesystem passed from ext3 to ext4, but is Zimbra considering size on disk or message sizes? In the second option, as I would expect, the size count shouldn't change. An user shouldn't matter what's the account size ON DISK.

As I sad, at first sight the account seems to be fully migrated on the new server, but I cannot be totally sure, I have tons of mails and subfolders in that 4G of mail.

How can I be sure it moved everything?
Can I trust zmztozmig?