I seem to recall that this question has been asked before. But a
search of the archives via Google didn't turn up anything.
My mail system is currently running on a temporary server. I have
rebuilt my primary server and am ready to migrate back onto it. I can
copy over the maildirs with no problem, but I was wondering about the
Since both servers are running the same version of Courier installed
with the same settings, I think I should be able to move the queue
over to the new server simply by copying over the /var/spool/courier
directory structure (while Courier is shut down on both servers).
Will this work?
Definitely not. It's good that you asked first. You just saved yourself a
lot of grief.
Is there a better way to do it?
Start the new server. Verify that it works, and it's accepting mail.
On the old server, put ":[a.b.c.d]" in esmtproutes, restart the old server
and run "courier flush".
Let Courier forward everything in its mail queue to the new server.
The goal is to shut down the old server, rsync the maildirs and queue
files to the new server, and then start up the new server with a
minimum of downtime for the users.
Unfortunately, I can't test this procedure without building a third
Courier server which I don't currently have the hardware for.
You don't really need to do anything here. Move the maildirs, then leave
the old server running for a week, until everything gets flushed from its
queue during ordinary course of business.