Rsync to backup dbox with SIS

[ash-dovecot at comtek.co.uk]

We will be deploying a replacement Dovecot server soon, and we are
planning to use maildir for the primary storage, but with an archive
namespace using mdbox (or perhaps sdbox), and SIS.

Our backup servers and (luke)warm spare server need to obtain full
copies of the mail store. For the maildirs I know I can simply use rsync
(we already use it here).

I'm a little wary of using rsync with mdbox and SIS though.

Obviously we would have to use the -H option of rsync to avoid
duplicating the hard linked data, does anybody have any experience with
how this scales? I've considered simply rsyncing the
/var/mail/dovecot/attach/??/??/hashes folders. Is there a tool that can
reconstruct the /var/mail/dovecot/attach/??/??/*-* links for a list of
messages in that case?

I'm aware of "doveadm backup", and (although it currently throws up a
few errors) it seems like it might be a valid solution for our warm
spare server. Our backup servers, on the other hand, aren't supposed to
be visible to the production machines, with the exception of the backup
machine sshing in to do an rsync each night. We can't install dovecot on
them.

To perform partial email recovery in maildir, we can simply log into a
backup server, grep for emails of interest, and then scp them into a
maildir new/ subfolder on the mail server to recover them.

What about using dbox? I can identify
/var/mail/dovecot/archive/ash/dbox/storage/m.* files, and identify
necessary attachments under /var/mail/dovecot/attach/??/??/ but once
I've copied them over to the mail server is there a safe way to import
them? Actually, converting to a maildir style file would be adequate if
there is a script anywhere to do this. We'd still rather be backing up
the deduplicated mailstore for obvious reasons.

Has anybody got any suggestions?

I'm aware of "dsync backup questions" (
https://www.dovecot.org/list/dovecot/2013-February/088070.html ) but
there didn't really seem to be a solution.

Thanks,

Ash

PS Our current server has 257 users (though perhaps 100 are active),
using around 225G in total.

PPS  Proposed new server configuration:

mail_location = maildir:~/Maildir:LAYOUT=fs
mail_attachment_dir = /var/mail/dovecot/attach
mail_attachment_fs = sis posix
mail_attachment_hash = %{sha1}
mail_attachment_min_size = 128 k

namespace _archive {
  list = yes
  location = mdbox:/var/mail/dovecot/archive/%n/dbox
  prefix = Archive/
  separator = /
  subscriptions = yes
  type = private
}

namespace _private {
  inbox = yes
  type = private
  separator = /
  subscriptions = yes
  prefix =
}




---

To opt-in to receiving communications from us or to update your email preferences please go to https://lists.comtek.co.uk/prefs.
To be removed from receiving all communications from the Comtek Group, please unsubscribe at https://lists.comtek.co.uk/prefs and accept our apologies for any inconvenience caused.

The Comtek Group respects your privacy. Please find our privacy policy at http://www.comtek.co.uk/privacy-policy

This email and any attachments are confidential. If you are not the named recipient, please notify the sender immediately.
The unauthorised use, disclosure, copying or alteration of this message or its attachments is strictly prohibited.
Opinions expressed in this message are those of the individual and not Comtek Network Systems (UK) Ltd unless indicated by an authorised representative independent of this message.
Comtek Network Systems does not accept responsibility for any changes to this message after it has been sent.

Company Details: Comtek Network Systems (UK) Ltd.
Registered Office: Comtek Network Systems (UK) Ltd, Unit 108, Tenth Avenue (Zone 3), Deeside Industrial Park, Deeside, Flintshire, CH5 2UA.
Comtek Network Systems (UK) Ltd is a company registered in England and Wales with company number 05929974.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://dovecot.org/pipermail/dovecot/attachments/20190125/9f8c63e6/attachment.html>