Re: HA, failover and load balancing / howto?

Are those geographical copies, or geographical subsets? Multi-master
replication is hard with postgres (read: probably not going to happen) but
if you can partition your data up so that you have one writer for a
subset of records, that could work quite well. Especially if you have rich
clients that can afford fast links between your regional servers.

On Sat, 4 Aug 2007, hanasaki wrote:

> I have some web applications and rich clients that need to
> geographically localized copies (for network latency reasons) of a
> database (East Coast, Central, West Coast and Japan)  These will be
> mostly read however there will be full CRUD activities going on.  I
> think this means that there will be a cluster in each region to deal
> with load and single failures and when a whole region perhaps dies,
> clients will fall back to another region.
>
> ex:
>     4 servers for load East Coast
>         - db and webservers
>     4 servers for load Central USA Coast
>         - db and webservers
>     4 servers for load West Coast
>         - db and webservers
>
> The web applications (Java, tomcat, ejb3, jboss4, php)  If one one, or
> more web or db servers die, the others in the region are still used (ie:
> just 'degraded')  If all the db servers die in a region, the web server
> and applications will hit the db servers in another region)
>
> How can all of this be setup and configured and how can failed db
> servers be brought back online and updated to sync into the clusters?
>
> Also looking at the pro/con of doing this in Postgres vs mysql
>
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