On Feb 24, 2010, at 5:08 PM, Adrian Overbury wrote:
> Terry Barnum wrote:
> >
> > - configure new postfix/dovecot server to be in correct domain (conf files,
> > certificates)
> > - setup users and passwords on new postfix/dovecot server
> > - use imapsync to pull all email from old server to new postfix/dovecot
> > server
>
> I think that there's an important step here that I always use when I'm doing
> a mail migration. It could really go anywhere above the 'wait for a Friday
> night' step, really. "Reduce the TTL on the domain to something quite small,
> ie: 5 minutes." The point of this is that you'll get an idea rather quickly
> of whether or not it works and, if it doesn't, you'll be able to change it
> back without a portion of the users experiencing long downtimes because of
> DNS records pointing to the wrong server.
Thank you Adrian. It was suggested to me that swapping IP addresses of the old
and new servers might be a safe way to accomplish this too just in case DNS
caching still pointed to the wrong server for some users.
So an updated recipe could be:
- configure new postfix/dovecot server to be in correct domain (conf files,
certificates)
- setup users and passwords on new postfix/dovecot server
- use imapsync to pull all email from old server to new postfix/dovecot server
- wait for a Friday night
- swap IP addresses of old server and new postfix/dovecot server
if all goes well {
- use imapsync again to pull any new email from old server to new postfix
server
- turn off old server
}
else {
- swap IP addresses back
}
Terry Barnum
digital OutPost
San Diego, CA
http://www.dop.com
800/464-6434
