[isf-wifidog] Multiple Portal Administration and Reports

Benoit Grégoire benoitg at coeus.ca
Sam 8 Mar 17:13:41 EST 2008


On Friday 07 March 2008, Andrew wrote:
> Hello List-
>
> I have setup a second portal server to provide failover for my primary
> server (because of my environment I have periodic disruptions in ISP
> connection to the primary server).  The secondary server is hosted at a
> different physical location.  I have copied my database to the secondary
> server and it seems to work OK.
>
> Is there some way to easily manage the secondary server so I do not need
> to copy the database each time I add a new node to the primary server?
> Also, I assume some statistical data will end up in the secondary
> database, so is there some way to run a 'combined' report from one portal
> that pulls statistics from both databases?

I'm affraid there is currently no simple way to do so.  Basically, wifidog 
need a single thing for multiple auth servers to serve the same gateways: a 
replication system where:
-All replicants are writable EVEN DURING A NETWORK OUTAGE
-Where the writes to both (or more) databases will be synched when 
connectivity is restored.

That means  asynchronous (sometimes called lazy) multi-master replication.  
The entire wifidog db has been designed with it it mind (there aren't any 
sequences anywhere).  While there are many replication solutions for postgres 
(see list later), there is a shortage of good ones for asynchronous 
multi-master.

Software offering replication on postgres:
http://bucardo.org/ (Need to specify tables individually)
http://pgpool.projects.postgresql.org/
http://sequoia.continuent.org/
http://www.postgres-r.org/
http://www.pgcluster.org/ (Synchronous multi-master)
http://www.slony.info/

Some background info:
http://en.wikipedia.org/wiki/Multi-master_replication
http://www.postgresql.org/docs/8.3/interactive/high-availability.html

At a glance, the only solution that could work is Bucardo, but the way it is 
configured (table by table) would make it a nightmare to maintain.
-- 
Benoit Grégoire
Technologies Coeus inc.


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