prepare large site migration

[Kjetil Torgrim Homme]

On Sun, 2006-04-30 at 21:42 +0200, Andrzej Kwiatkowski wrote:
> I'm preparing for migrating about 30k account from
> Netscape Messaging Server to Cyrus (yeah... cyrus rules, NMS sucks ;-) )
> 
> And now i want to find out the best solutions for this.
> NMS has very similar structure of mailboxes
> 
> 1. Imap Copy
> 2. Tar ; untar mailbox and reconstruct,
> 3. Get mails from old mailbox and send directly to deliver process or to lmtpd.
> 
> What is the best idea and the fastest.
> There are about 50Gigs of data.

only IMAP copy (I use imapsync) will preserve flags, and users will be
miffed if they lose \Seen, I'm sure.

the downside is that you'll be lucky to transfer more than 1 MB/second,
so it'll take a day!  of course imapsync will move one account at a
time, but you'll have to route individual users to the correct server
during the transition if you don't shut it all down.  perhaps use
Perdition temporarily?
-- 
Kjetil T.