← Back to team overview

maria-discuss team mailing list archive

Re: WL#4925 and multi-source replication


On Wed, Mar 13, 2013 at 4:34 PM, Greg <skygreg@xxxxxxxxx> wrote:
> Hi,
> I'm testing multi-source replication with 6 sources, it works great !
> Now I'm at the "HA" state, testing a master multi-source with DRBD. To do a
> safe switch between masters, I have to enable sync_binlog=1 and then the
> master delay grow...

Hi Greg

I realize you said in this thread that you are already committed to
use DRBD, but just to educate the list if nothing else: Is MariaDB
Galera  Cluster an option for the master database? The difference with
Galera in this case would be:

 - It is not dependent on innodb_flush_log_at_trx_commit needing to be
1, and with some additional configuration/verficiation you could also
safely do sync_binlog=0.
 - Even if you choose to set both of these to 1, I've found that the
performance penalty from Galera is much smaller (or nonexistent)
compared to DRBD. The difference is that Galera replication happens
completely separately from syncing data to disk, whereas DRBD makes
syncing data to disk slower and this is unfortunate as it is already
the slowest part of committing a transaction.

Other than this I agree with Kristian that DRBD in general is a robust
and simple HA solution. (It sounds like in your use case the slow
failover times are not an issue, which is true for many applications
of course.) I just wanted to introduce an alternative.

Disclosure: I nowadays work for Codership, although my experience with
Galera comes as being an end user.


+358-40-8211286 skype: henrik.ingo irc: hingo

My LinkedIn profile: http://www.linkedin.com/profile/view?id=9522559