Backup methods

Albert Shih Albert.Shih at
Thu May 10 16:50:04 EDT 2018

Le 10/05/2018 à 16:08:32-0300, Anatoli a écrit


> In both cases, a copy of the master data is made, which requires twice the
> space of real usage (Cyrus Backups tries to apply compression on stored data,
> not sure how well it works).

In ZFS with lz4 (standard compression on ZFS) you got 1.18 ratio (3.57 To
on disk for 4.05To of data) so not very good.

I use lz4 because it's got same performance than no compression.

I didn't try gzip on mail but gzip can be very impressif on ratio but eat
lot of cpu.
> What is really needed, IMO, for SME environments is the ability for Cyrus to
> sync to disk all data, so one can take a hot copy of that data with standard
> UNIX tools and then handle it accordingly. Once a recovery is needed, one just
> copies a backup to the Cyrus dir and starts the service. The data would be in
> the exact same state as when the backup took place. This is discussed in the
> github issue mentioned in the previous mail.

I fully agree.

In fact 7 years ago when we renew our mail server I already try cyrus and
dovecot (we come from courier-imap), and we choose dovecot because it's
very easy to backup (and manage) for old_unix_admin. Just put in the
crontab some rsync that's all, one mail = one file, etc.

Now we choose cyrus-imap over dovecot (so for next 7 years) because all the
feature cyrus got. But yes if cyrus got something like mysql_dump or
pg_dump_all that would be super nice.


Albert SHIH
DIO bâtiment 15
Observatoire de Paris
xmpp: jas at
Heure local/Local time:
Thu May 10 22:43:47 CEST 2018

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