I'm getting ready to migrate all users from a SquirrelMail/WebMail/GroupOffice Mail system to Zimbra. I've tested the ImapSync utility and it seems to do what I need, but it seems a little slow for the timeframe I have. Essentially, I have 37,000+ accounts to migrate in a 3 day period. Does anyone know of any other options out there that I may have? Also, does anyone know the type of load imapsync has on servers? From what I can tell, it's not too terrible. My current plan is to do a bunch of imapsync processes at the same time, but I don't want to overdo the load on the source servers or the Zimbra servers.
Anyone else have any thoughts?