[Dovecot] DSYNC needs a lot more documentation

[Timo Sirainen]

On Sat, 2010-08-21 at 09:51 -0700, Marc Perkel wrote:
> Ok - when I type dsync at the command line it says:
> 
> usage: dsync [-C <alt char>] [-m <mailbox>] [-u <user>] [-frRv]
>    mirror <local mail_location> | [<user>@]<host> | <remote dsync command>
> 
> However the man page mentions nothing about any remote commands. 

I'm not really sure what more to write about it. It just needs to
execute the dsync some way.

> There 
> is a reference to ssh in one example but there isn't any kind of 
> overview as to how this all ties in. Does dsync pick up information from 
> dovecot.conf or dovecot to know where the email is an what format it is 
> in? Does dovecot need to be running on both ends? 

I added text about these and some other stuff. See updated
http://wiki2.dovecot.org/Tools/Dsync

> Does this run 
> continuously once you start it or does it need to be run once a minute? 

It's not continuous.

> So - ServerA is running dovecot. On ServerB I want to have a live copy 
> so that if the drives on ServerA die I can recover on ServerB? Does it 
> do that?

You can do that, yes.

> I want to run dovecot on two servers so that if either server fails the 
> other seamlessly takes over and when the other comes back up they resync 
> as if nothing had happened. Is that possible? If so - how?

Yes, as long as you call dsync for all users often enough. There's no
super easy way to do this yet, see my other recent emails about this in
some thread with dsync subject..

> If it just does backups, how is it different than rsync?

It's faster.