Postfix - how to delete all the old emails?

Question

I have a VPS server that manages the post. It has postfix, dovecot, spamassassin, etc. The OS is ubuntu. Using POP only.

postconf mail_version
mail_version = 2.10.1

This server has about 15 email boxes at different domains. Some mailboxes have more than 200.000 emails received in the last 10+ years.

I want to configure outlook in a tablet with 250GB of SSD. For obvious reasons I do not want to have here the history of all the emails of the last 10 years. For that I have the desktop computer.

The folders structure is:

(for email [email protected])
/var/vmail/example.com/info
/var/vmail/example.com/info/cur
/var/vmail/example.com/info/new
/var/vmail/example.com/info/tmp
/var/vmail/example.com/info/sieve 

Questions:

1. How to delete the emails from the server, so that outlook will download only new emails after it is configured? Is it enough to remove only the files in the new folder? Or can I delete the new folder and postfix will re-create the folder once new post is received?
2. How to configure an additional IMAP? Now only POP3 is configured in the server. So how to add IMAG to the already existing and working fine POP3? If it's too long to explain, maybe you can send some tutorial? I tried to google it, however all the tutorials I found seem to describe the whole configuration of the mail server from scratch. If in order to answer this question you need more info, please let me know and I'll collect some config.

Answer 1

I would suggest configuring IMAP first – then use an IMAP client to delete everything, or to move all old mail to a folder. I'm not sure how well Outlook would cope with 200k messages, but all IMAP apps have the option to download "headers only" (which should be less 1 kB per message), so disk space shouldn't be an issue even with all messages kept.

Otherwise:

1. Remove files from cur and new, but keep the subdirectories themselves. If you remove the actual subdirectories, Postfix might fail to recognize the path as a Maildir (e.g. it might think it's an MH-format folder instead).

   Also remove all dovecot* index/cache files that you find nearby (they should be in the same directory).

2. Both POP and IMAP will be provided by the same Dovecot service and will use the exact same configuration. (Postfix is not involved; it just deposits the messages and from there they belong to Dovecot.)

   Assuming the current Dovecot configuration is correct, the only thing you should need to do is install the dovecot-imapd or similarly named package (if your distro splits it up) and make sure Dovecot's protocols = option includes imap. Since it's just a new module in the same service, it will automatically use the same mailbox paths, user database, etc.

   If it doesn't work, step 2 is "look at system logs" and step 3 depends entirely on what went wrong. Unlike setting up a new server from scratch, it's difficult for anyone to write a complete tutorial for adding something to an unknown system since the tutorial cannot reliably assume anything about the setup – so only 10% of it is actual step-by-step configuration; the other 90% would be general problem investigation skills.