I would move the imap.* to a neverland address while doing the switch so users arn't opening email while files are being rsynced.
OR, just add a firewall rule to old server blocking imap. I would also send a notice to uses a few days (preferably a week in a large setup) saying that email may be intermittently unavailable at 9pm on bla bla day while we perform maintenance on our servers to improve our service to you. Have a place on your site where they can check the status of the move and it should avoid "most" phone calls. Thomas Suckow On Thu, Aug 13, 2009 at 9:48 PM, Timo Sirainen<t...@iki.fi> wrote: > On Aug 14, 2009, at 12:36 AM, Gary Chodos wrote: > >> We have to replace one mail store (foo.example.org) with another >> (bar.example.org). I rsync'd the maildirs from foo to bar today and >> the plan is to hold all delivery (in the SMTP server) on foo over the >> weekend, rsync again (this time it should be much faster since the >> large xfer already occurred today), then flush the SMTP queue on foo >> towards bar, direct all new deliveries to bar.example.org. Users >> currently access their IMAP mailboxes via imap.example.org. I plan to >> just 'flip the switch' at DNS so imap.example.org points to >> bar.example.org (instead of foo.example.org) so users don't have to >> change anything on their end and should not even notice this change. > > And I guess you also thought about the DNS cache TTLs? > >> Is there anything else I should think about to mitigate users noticing >> a change? > > If the maildirs are identical and no mails get lost during the move, that > should be it. > >> Does the fact that the mail filenames include >> 'foo.example.org' in the file name (while new deliveries to >> bar.example.org will include that new hostname) spell trouble later on >> or can I ignore it? > > Filenames don't matter. > >> And finally, dovecot on foo.example.org is 1.1.7 while the new server >> is running 1.1.16. I don't think that should be an issue, but >> mentioning it just in case. > > Whenever upgrading it's a good idea to go through the items marked with "*" > in NEWS file (http://dovecot.org/doc/NEWS-1.1) There aren't many usually. >
