How to backup maildir

Robert Moskowitz rgm at
Sun Feb 10 13:55:03 EET 2019

On 2/10/19 2:24 AM, Christoph Haas via dovecot wrote:
> Hello Robert,
> ----- Nachricht von Robert Moskowitz via dovecot <dovecot at> 
> ---------
>      Datum: Sat, 9 Feb 2019 22:50:24 -0500
>        Von: Robert Moskowitz via dovecot <dovecot at>
> Antwort an: Robert Moskowitz <rgm at>, Dovecot Mailing 
> List <dovecot at>
>    Betreff: How to backup maildir
>         An: Dovecot Mailing List <dovecot at>
>> I have been thinking, and reading, on how to back up my mailserver. I 
>> have not found any approach that seems ready to use.
>> I have run years without any backup, but would really like to have 
>> something in place.
> you're a really lucky guy! - I've been struck in the past for such 
> carelessness on the one or other machine with dataloss ;-)

Absolute laziness.  No real excuse.   Also all users were POPing until 2 
years ago.  Finally got everyone on IMAP just in the last year.  So a 
server loss would have been an inconvenience.  For myself, almost 
nothing in the IMAP store, everything in local folders that I have a 
separate backup procedure.

>>   I figure I can attach a USB drive and backup to that, then from 
>> there rsync to something elsewhere. Further if that USB drive is a 
>> full mailserver image, I actually have a 'hot backup' where I only 
>> have to put the backup drive into a system and boot up at the last 
>> backup.
>> But this means properly copying all of /home/vmail and probably 
>> /home/sieve plus the /var/lib/mysql
> Are you aware of the dovecot command "dsync"? (man dsync or 
> This could be an approach of using dsync:
> dsync backup -o plugin/quota= -f -u $user backup 
> maildir:/mnt/USB/dovecot-backup/Maildir/$user/mail

My search foo is weak.  This is a long documented fact.  I did spend a 
number of hours searching and reading before opening my mouth here, 
fully expecting to put more than my toes in.

I will read up on dsync.

>> Are there good tools that nicely does this?  Or do I choose a time 
>> late at night (only I am sometimes in non-US timezones) to shut down 
>> all services and just use rsync?
>> And stopping services itself is thought provoking.  What if Dovecot, 
>> amavis, mysql, or whatelse is in the middle of writing out a mail 
>> file what happens to that file and restart.
>> Just scary stuff and, in part, why I have never tackled this in the 
>> past.
>> thanks for all feedback
> ----- Ende der Nachricht von Robert Moskowitz via dovecot 
> <dovecot at> -----
> It really depends on how important your data is to you ... But you 
> should really think about a general backup-strategy!
> "Mr. Google" can help you to get some ideas how YOUR backup-strategy 
> could look like...
> Also there is much input for backing up dovecot with it's different 
> mail storage flavours.
> - But you have to invest some effort on your own, to search, read, 
> evaluate and finally choose what's fitting into YOUR setup!

I have been and have been searching.  Some hits, but so far nothing was 
hitting the spot.  But, I will blame my dyslexia that my search foo is 

> But as an starting point:
> I'm using a for _MY setup_ modified and adopted version of Klaus 
> Tachtler's dovecot-backup script:
> ... mixed it with Borg Backup:
> ... some further encryption, cloud storage and ... and ... and other 
> stuff.

I will check both of these.

> But as above mentioned:
> YOU have to think about the grade of your paranoia level, how 
> importand the data is to you in case of an data loss, time and money 
> you are willing to invest and build upon this YOUR PERSONAL backup 
> strategy.
> - Sadly there is no one-size-fits-all!

If there was, we would not be here, I suspect.

> Last famous words:
> I've looked at your vita and was wondering about your post - you were 
> writing RFCs, but have no clue about backing up your mail-data??? 
> Strange ...

MY mail is well backed up.  Locally so that I can read on a plane and 
the like.  I have been running one flavor or another of my own mail 
server since '95.  I switched to dovecot 6 years ago.

My home file server is backed up 4 ways around.  And I have lost file 
servers and file server drives over the years.  Upgrading my file server 
is the next project.

But I write RFCs.  I have been using geany for XML for a few years. I 
'code' in English.  I have not written computer code since probably the 
late 80s.  I never coded in C, but I did use B for a while!  These days 
I can write simple scripts when forced to.  :)

My 'spare' time these days is working with armv7 boards.  I have been 
using Cubietech since '13, recently got an Odroid HC1 and that is what 
this server will be.  For the most part you will find me on the 
Centos/Fedora lists and their arm lists.  Occasionally I will put on my 
Kevlar suit and ask something basic on a product list.

But as a result of doing this, recently there is a new SElinux policy 
for permitting Dovecot to access Mysql.  It has already been patched 
into Fedora 28 and up.  Sometimes it pays to ask for help.

> Nevermind! Just my 2ct - hope this helps
> Christoph.

Euro ct?  :)

Better than US ct!

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