[Kolab-devel] Kolab: Cyrus replication HA option

[Kevin Baker]

Interesting... some questions below

> On Thursday 21 July 2005 17.18, Kevin Baker wrote:
>> I will probably spend some time on it over the next
>> month.
>>
>> I'd be curious to know what simpler solutions you have
>> tried... rsync with, stop cyrus and re-rsync then start
>> is
>> the best I have heard recently.
>>
>
> We have two different solutions in semi production to see
> wich one pans out
> best.
>
> 1, Snap shot the fs, dump, copy restore
So the dump is a complete backup,
The copy is scp to the other server,
the restore is stop cyrus move files over start cyrus?

Do you stop Cyrus before the snapshot? Does the snapshot
require additional space for the mailstore duplicate, or
is it a small sized snapshot with sym links then rsync?

Does this require a cyrus reconstruct?


> 2, Snap shot the fs, mount the snapshot and rsynch it to
> the standby.
Same as above is the snapshot requiring extra storage? IE
40GB's mail spool, 40GB snapshot... or 40GB mailspool,
snapshot 0+changes.




> A lot easier then messing with IMAP things, but the lag is
> as large as the
> synch time between hosts.
I agree... this has been an on going issue for me with
Cyrus. Considered moving to DBMail for a while to use
MySQL replication, but it is not as feature rich.



> but for a normal server, with some 3-400 GB storage, we
> can dump and copy and
> restore fairly quickly.

So what is the lag? Is your hot "backup" server 5 minutes
behind? or....


Thanks so much for your response... I'd love to have a
method working in production that could be published on
the wiki. It'd be great to have a "standard" way to
provide a low cost "hot backup" setup for two server
clusters. Sort of a RAID-1 for email...


Kevin Baker


> rgds
>
> Matt
>
> --
> Matt Douhan
> www.fruitsalad.org
>