Re: [Postgres-xc-general] Table distribution/replication and other things

On Wed, Jan 30, 2013 at 5:46 PM, Christophe Le Roux
<chr...@fr...> wrote:
> Thank you for your answers.
>
>
>
> About the third question, I don’t want to use standby server for now (except
> for GM standby).
>
> The cluster would be 4 servers :
>
>
>
> A – GTM server
>
> B – GTM proxy, coordinator and datanode server
>
> C – GTM proxy, coordinator and datanode server
>
> D – GTM standby server
>
>
>
> All tables of all databases are “DISTRIBUTE by REPLICATION” (postgres-XC
> capability). So we have same data at the same time on datanodes B and C.
>
> So if B server fail , C server will do the job.
>
> If C server fail, B server will do the job.
>
> B and C server talk to A server (for GxId, sequence,..) but if A server
> fail, we can promote D server to the master GTM.
>
>
>
> Now, we suppose that : server A and B are located in DC1, and serveur C and
> D are located in DC2.
>
> B and C will do the jobs and talk to A server (for GxId, sequence,..).
>

If I read correctly, B and C will be in different DCs which typically
mean that they will connected on a slow WAN link. Since for
replication, coordinator needs to send a lot of information to/for the
datanode, I am not sure if this would work well. But then it depends
on how much workload you are really putting on the server. It will
also depend on what kind of queries you would be running. I don't
think anyone has tried (yet) to keep the datanodes on different DCs,
but give it a try.

Thanks,
Pavan
-- 
Pavan Deolasee
http://www.linkedin.com/in/pavandeolasee