Transition from one server to another.

[Anders Wegge Keller]

 A frind of mine and I are running a dedicated server, that among
other things host mail for ourselves and friends and families. All in
all about 15 different domains with 35-40 users. The machine in
question is old, so we are doing a slow transition from the old server
to the new one. So far, we've managed to move web hosts
seamlessly. Due to the technical capabilities at some of the user
base, it would be nice to get to a setup, where we can move individual
users imaps from the old server to the new one, as we get the time to
visit them.

 I have an idea how such a transition could go:

 1. Upgrade the old dovecot 1.2.15 to 2.1.whateveritis from debian
    squeeze backports.

 2. Set dsync up to replicate mails from the old server to the new
    server. I know that 2.2 is recommended, but with a limited amount
    of user, I'm willing to take a performance hit.

 3. Migrate my parents &c to use the new server.

 4. When all users have been moved on to using the new server, upgrade
    MX records for the domain to point at the new server.

 5. When all MX records are updated, decalre success.


 Is this feasible, and what would the risks be. For instance, during
step 4, mails are bound to arrive at bothe the old and new server for
some time. Will this cause problems?

 Is there a simpler solution to the problem?

-- 
/Wegge

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