[Dovecot] dsync redesign

[Charles Marcus]

On 2012-04-02 7:15 PM, Micah Anderson <micah at riseup.net> wrote:
> Charles Marcus<CMarcus at Media-Brokers.com>  writes:
>> On 2012-03-27 11:47 AM, Micah Anderson<micah at riseup.net>  wrote:
>>> One would be the ability to perform *intelligent* incremental /
>>> rotated backups. I can do this now by running a dsync backup
>>> operation and then doing manual hardlinking or moving of the
>>> backup directories (daily.1, daily.2, weekly.1, monthly.1, etc.),
>>> but it would be more intelligent if this were baked into the
>>> backup process.

>> There are already numerous tools that do this flawlessly - I've
>> beenusing rsnapshot (which uses rsync) for this for years.

> Are you snapshotting your filesystem (using LVM, or SAN, or similar)
> before doing rsnapshot? Because if you aren't then rsync will not
> assuredly get everything in a consistent state.

No, and you are correct... but I run it in the middle of the night, and 
the system is only barely utilized at the time, so the very minor 
inconsistencies are not a problem overall.

I will, however, be changing this to using FS snapshots once I get my 
mailserver virtualized (already being planned for when our new office 
location comes online), so that will allow me to perform snapshots 
multiple times during the day (I'm thinking 4 times per day will be enough).

>> I don't know if Timo should be spending his time reinventing the
>> wheel.

> dsync backup is already here, and it is quite useful.

I'm not saying it isn't, I'm just saying that there are already *plenty* 
of different backup tools, and I don't see the sense in Timo spending 
lots of time on creating a new one just for dovecot. His time would be 
better spent just making it easier for any other backup tool to work better.

>> Although, one interesting piece that I am hopeful I'll be able to
>> implement soon (with Timo's professional help) is the ability to
>> easily and automatically map my rsnapshot snapshots directory to a
>> read-only 'Backups' namespace that automatically shows the
>> snapshots by date and time as they are produced. This way users
>> could 'go back in time' anytime they wanted without having to call
>> me... :)

> Interesting idea, would be a great one to share with the community
> if you decide to do so.

Absolutely - that is already on my list for when I pay Timo's company to 
do this - document it on the wiki. Hopefully if any code changes are 
needed to make it work right, they will be minor.

-- 

Best regards,

Charles