[Dovecot] Best way to migrate from Qpopper to Dovecot
Hi List,
what do you think is the best way to migrate (to a new maschine) round about 30000 mboxes (Qpopper) with an amount of 43Gigs data, to maildir format (Dovecot). I think there are two ways:
- stop services (smtp and pop3) on the old maschine
- copy the mboxes to the new maschine
- run a conversion script (for excample: "Perfect_maildir" http://perfectmaildir.home-dn.net/)
- start the services on the new maschine (smtp and Dovecot)
- tell the users to use the new server (from the day X) with the new feature (imap)
- stop the smtp on the old maschine on day X
- leave the old maschine active for a month or so (let users get their "old" mail)
With the first alternative we have a high downtime, because of copying the mboxes and converting the stuff.
What do you think?
Thanks Torsten
Torsten wrote:
- stop services (smtp and pop3) on the old maschine
- copy the mboxes to the new maschine
- run a conversion script (for excample: "Perfect_maildir" http://perfectmaildir.home-dn.net/)
- start the services on the new maschine (smtp and Dovecot)
Hi,
So, parts of these processes can be parallelised:
- Copy mailbox data from old machine to the new one. Leave production services running.
- Shut-down services on old machine.
- Update the mailbox data on the new machine using rsync.
- Convert mailboxes to Maildir format, eg using Perfect_maildir or mb2md.
- Start services on new server, update DNS aliases, etc.
Now, ideally, you'd do each of the above _per-user_ -- disabling just *one* account at a time whilst it was being updated. This will require a bit more work and infrastructure support (eg a front-end POP/IMAP proxy).
Oh, and in principle, I see no reason why you can't have both SMTP services running at the same time..
Cheers, David
David McBride dwm@tastycake.net
Hi David,
thanks for your suggestions. You`re right, if I use rsync the smtp service on the old maschine could be active when copying the mboxes. Without rsync a loss of emails is possible.
Another thing crossed my mind, on the new maschine we have a new directory structure like "/var/mail/domain/first_letter_of_username/username/maildir/". The directory structure on the old system is flat like "var/mail/username". So I have to script a lot. Hmm let`s see, maybe I use my second alternative (no migration of data).
Thanks Torsten
On Mon, 19 Mar 2007 17:39:03 +0000, David McBride dwm@tastycake.net wrote:
Torsten wrote:
- stop services (smtp and pop3) on the old maschine
- copy the mboxes to the new maschine
- run a conversion script (for excample: "Perfect_maildir" http://perfectmaildir.home-dn.net/)
- start the services on the new maschine (smtp and Dovecot)
Hi,
So, parts of these processes can be parallelised:
- Copy mailbox data from old machine to the new one. Leave production services running.
- Shut-down services on old machine.
- Update the mailbox data on the new machine using rsync.
- Convert mailboxes to Maildir format, eg using Perfect_maildir or mb2md.
- Start services on new server, update DNS aliases, etc.
Now, ideally, you'd do each of the above _per-user_ -- disabling just *one* account at a time whilst it was being updated. This will require a bit more work and infrastructure support (eg a front-end POP/IMAP proxy).
Oh, and in principle, I see no reason why you can't have both SMTP services running at the same time..
Cheers, David
Torsten wrote:
Hi David,
thanks for your suggestions. You`re right, if I use rsync the smtp service on the old maschine could be active when copying the mboxes. Without rsync a loss of emails is possible.
I think you mean 'POP' or 'IMAP' rather than 'SMTP', but yes.
Hmm let`s see, maybe I use my second alternative (no migration of data).
In general, I'd advise against that - that way lies madness.
In particular, users tend to get confused if they have multiple different mailbox interfaces. Plus you then have to maintain two completely independent mail services rather than just one (including backups and everything else that that entails.)
Usually it's much less effort _in the long run_ to migrate the data.
Cheers, David
David McBride dwm@tastycake.net
Hi Torsten,
You can try installing an IMAP daemon on the old box and use a tool like imapsync to copy existing e-mails to the new box. This will allow you to reduce downtime to the user whose mailbox is being copied at that point in time.
While this goes on, you may need a POP3/IMAP proxy like Perdition to proxy POP3/IMAP4 requests to the correct box that contains their mailstore.
Hope this helps in some way.
Cheers.
On Mon, 19 Mar 2007, Torsten wrote:
Hi List,
what do you think is the best way to migrate (to a new maschine) round about 30000 mboxes (Qpopper) with an amount of 43Gigs data, to maildir format (Dovecot). I think there are two ways:
- stop services (smtp and pop3) on the old maschine
- copy the mboxes to the new maschine
- run a conversion script (for excample: "Perfect_maildir" http://perfectmaildir.home-dn.net/)
- start the services on the new maschine (smtp and Dovecot)
- tell the users to use the new server (from the day X) with the new feature (imap)
- stop the smtp on the old maschine on day X
- leave the old maschine active for a month or so (let users get their "old" mail)
With the first alternative we have a high downtime, because of copying the mboxes and converting the stuff.
What do you think?
Thanks Torsten
Hi Tan (or is that your surname),
thanks very much. This is an interesting tool, which I have to test.
Regards Torsten
On Tue, 20 Mar 2007 08:36:46 +0800 (SGT), Tan Shao Yi tansy@pacific.net.sg wrote:
Hi Torsten,
You can try installing an IMAP daemon on the old box and use a tool like imapsync to copy existing e-mails to the new box. This will allow you to reduce downtime to the user whose mailbox is being copied at that point in time.
While this goes on, you may need a POP3/IMAP proxy like Perdition to proxy POP3/IMAP4 requests to the correct box that contains their mailstore.
Hope this helps in some way.
Cheers.
On Mon, 19 Mar 2007, Torsten wrote:
participants (3)
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David McBride
-
Tan Shao Yi
-
Torsten