For every u...@domain.tld I created a u...@backup.domain.tld where he
could look up deleted messages (archive).
I then made u...@backup.domain.tld's cur directory a shared directory to
u...@domain.tld but only with read privileges. So, anytime the user
wants to read his old messages, he only needs to read his .archive
folder, which is u...@backup.domain.tld's cur. No need to make the
filesystem read-only.
The difficulty is to make sure that every e-mail, sent or received, gets
backed up properly before being deleted. Relying on cron jobs is not an
option since the e-mail can be deleted and expunged before the script
has a chance to get executed and do the backup. So what I did is to
create a hidden sieve filter for every user's **main** mailbox
(u...@domain.tld) that automatically creates a copy of every incoming
message to the u...@backup.domain.tld mailbox. For outgoing e-mail, one
can do a bcc map in postfix (or the equivalent in other SMTP software)
that ensures that every sent mail is also sent to
user+s...@backup.domain.tld, then you can create a filter in the user's
**backup** mailbox (u...@backup.domain.tld) that filters on the
user+sent part of the e-mail and stores every e-mail sent to that e-mail
address to the .Sent directory in the u...@backup.domain.tld mailbox.
Finally, the backup.domain.tld doesn't even have to be declared in the
DNS nor in /etc/hosts and can be entirely virtual to the MTA (for ex. in
postfix that would only be added to virtual_mailbox_domains)
Yassine.
On 3/8/19 12:49 AM, Natu via dovecot wrote:
I have a dovecot server running under CentOS using maildir format. Due
to the issue with minimum blocksize for files I would like to offer some
kind of readonly archive using something like the compressed squashfs
where I would move messages to be archived to a maildir folder and then
convert "cur" directory into a squashfs and mount it in place of the
original directory so my biggest users could have readonly access to
older messages without it using so much disk space.
Has anyone tried anything like this before and is dovecot likely to
complain about the readonly cur directory? If the complaints are
minimal and didn't cause other problems it might be ok. Any better
ideas to implement something like this?
Thank You,
Natu
