Need help, migrating mail accounts from cPanel to DirectAdmin using rsync

[rerotey]

Hello,
i'm moving a domain from cPanel (CentOS 7, Dovecot v2.3.13) to DirectAdmin (CentOS 8, Dovecot v2.3.15), there are very few email accounts, but each account is immense (over 60GB).
i'll start off with my concern, and work backwards..
My main concern is that my client's email software (all Apple) will re-download all the emails if the UIDs are not preserved in the transfer..

i was going to use imapsync, but my understanding is that it cannot preserve UIDs because Dovecot itself manages them.

sooooo...
my idea is this:
Since both servers use Dovecot 2.3.x..
create all the same email accounts on the new server, using the same addresses and credentials..
and then just use rsync to overwrite the contents of each account on the new server in <domain>/mail/<domain>/<each_user>

once rsync is done, switch the DNS over to the new server and none is the wiser..

any thoughts are greatly appreciated!!
Thank you!

 

[Fauzul]

I'm pretty sure we've tried various methods of this and nothing was ever able to be performed as seamless as what we had wanted it too.

In both situations, regardless of how it was done -- I believe the mail client downloaded emails regardless simply because the method cPanel handles Dovecot and the way DirectAdmin handles Dovecot is just distinctly different.

Whereas cPanel dovecot has files that index where everything is and that doesn't get carried over to DirectAdmin, so.. your mileage may vary.

While I do believe your idea would work, I believe that any IMAP sync connection may still try to re-download all of the emails.

The worst instance we had with this was around 3TB of email. The other issue being that DirectAdmin Dovecot doesn't utilize hardlinks like what cPanel Dovecot does.

So if email accounts 1-5 have the same email, cPanel hardlinks to conserve space so those 5 accounts don't all have the same 10mb email -- whereas DirectAdmin shows as 50mb since there's no hardlinking

However, I wouldn't hold my breath and I would plan for the worst when dealing with such transitions.

 

[rerotey]

Thank you so much for your reply!
i have a little time until the migration, so i might do some tests..
But from what you say about the hardlink and the index issues, i might just play it safe and use imapsync..
Thank you so much!!