We've been putting off upgrades to our Zimbra server because we haven't been able to get a good backup. Apparently one of the full backups was corrupt and the incrementals couldn't work from it, but the fulls kept dying.
Last night I babysat the full backup that I started at 6pm. It just finished, 18 hours later. There are 426 users on the system and the backup (not using any of the options) takes about 400MB of disk space. During the backup the server load average hovers between 6-8 (usually it's 1-3).
This is just a 'zmbackup -f -a all'. Should it take this long? Last time we did a backup it was only taking three hours, but I don't know yet if user mailbox sizes have changed significantly.
I haven't tried the synchronous backup flag yet.
Thanks for any tips/pointers.