On Tue, 2010-02-09 at 16:53 -0500, Marc Fournier wrote:
> 
> > pgcluster-I design is not scalable. You will need *at least* 3
> cluster
> > machines and 1+1 load balancer + 1+1 replicator machines for a
> system
> > that is won't stop (at least for a while)
> 
> Please elaborate on this point ... you say you will need *7* machines,
> total?  Why?

You need at least 3 db servers. Current design is: If one of them fails
and comes back, it will need to take another host down, and re-sync from
it -- and 3rd machine will have all the load.

For the load balancer and replicator: You need to have a backup for
both. You *can* install load balancer to one of the db machines, but it
is will be a SPOF. I don't find installing load balancers to db servers
clever, because of overhead and such.

Same is valid for replicator instance.


> > Until PostgreSQL developers implement some way to share
> "shared_buffer"
> > data between more than 1 PostgreSQL machines, none of the solutions
> will
> > be scalable. PGCluster does have lots of overhead, including write
> > loads. The only gain is from SELECT queries. However, given the
> > complexity of the installation and infrastructure, I would not spend
> > more time on PGCluster on prod installations.
> 
> Odd, I found the installation process for 1.9 to be very
> straightforward and easy ... once I built/installed the binaries, it
> took me <15 minutes to get it configured and running where I could
> load databases and actaully see them on both sides ... was very
> impressed with that ... 


Did you test it under heavy load? I did.

-- 
Devrim GÜNDÜZ
Professional PostgreSQL Services, Training, 24x7 Support
Authors: PostgreSQL RPMs, PITRTools, PostgreSQL Replicator 
http://www.commandprompt.com/ XMPP: [email protected]
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