migrating emails from old server to new server

Question

(Bear with me, the whole idea of email setup is new for me)

I have a server configured with postfix, dovecot and roundcube, everything is set u correctly.

On the old server (Also using postfix), all the mails are in one file, I tried to migrate them to the new server(i.e copy the file to the new path of /var/spool/mail/$user and /var/mail/$user).

If I use from the terminal the command mail I can see the mails on the new server.

But when I try to access from roundcube, i get "Mailbox is empty"

I can see my sent mails in the folder /home/$user/mail/.Sent/cur/....

But each mail is a single file

Is there anything I'm missing, is the issue with dovecot because it uses another structure for the mails or something ?

Answer 1

First, let me clarify some basics for you.

• Mailbox format is the format you have on the old server. Its literally multiple message in one file
• Maildir format is the format you see in your home directory. These cur and other folders relates to this format.

If I guess correctly, you have a setup on the old server that tells to Dovecot to use mailbox format and read mailboxes from /var/spool/mail/$user, in the new server, the Dovecot is configured to use Maildir format and store them at /home/$user/mail. This can be configurable in the Dovecot config files, but I recommend you to do not touch it, since Maildir is better and Dovecot has a really good support for it.

All you have to do is install a mb2md utility on the new machine, convert all mailboxes to maildir format (before this, read its manual carefully) and transfer the resulting maildirs into the proper places.

I also recommend you to examine the Dovecot config files how it's configured currently and how can you potentially change the location of the maildir if/when you need it.

Answer 2

One option is to use imapsync utility to move the e-mails from old server to new server. This way you don't need to perform slightly risky data conversions.