Backing up and Importing IMAP folders

[Konstantin Khomoutov]

On Thu, 20 Oct 2016 09:18:12 -0400
Jerry <jerry at seibercom.net> wrote:

> I am running Dovecot with Postfix on a FreeBSD machine. There are
> problems with the drive and I cannot depend on it. Dovecot saves all
> mail in IMAP format. I want to back up the mail folders, install a new
> HD, install the latest FreeBSD OS and then reinstall my programs.
> Reinstalling Dovecot is simple, but how do I reinstall the IMAP
> folders? Can Dovecot backup the folders onto a CD and then import them
> when I reinstall it? My mail is kept under “/var/mail/vmail”. Should I
> just back up that entire directory structure and then restore it
> later?

That should work (just make sure Dovecot is not running to not have a
race between your backup software and the IMAP server and clients).

Alternatively you can use `dsync` to perform backup with a native
Dovecot tool.  It's able to sync mailboxes of any Dovecot user --
including synchronizing a mailbox to an empty (yet) spool.
You'll need to do a bit of shell scripting which would spin around
calling `doveadm user *` and feeding its output to something like

  while read user; do \
    dest="/var/backup/dovecot/$user";
    mkdir -p "$dest" && chown vmail:vmail "$dest" \
      && chmod 0755 "$dest"
    dsync -u "$user" backup "maildir:$dest" \
  done

Note that you will only need this if you don't want to shut down
Dovecot to copy its mail spool out.