[consulting] Distributed Loads, Failover and Dynamic Content

[Hugh Esco]

I'm working with folks who would like to physically
distribute their server load so that they might be 
prepared for peak demand as well as to provide for fail-over
as part of a disaster recovery plan.  

We're looking at rsync and such for static content.  But
I'm curious what strategies others might be pursuing for
syncing two or more servers which are hosting mirrored
content on dynamic platforms which are subject to local
manipulation between changes.  

I'm imagining some sort of hourly flatfile datadumps, which
would be diff'd and merged together with hourly restores.
With DNS round-robin being used to distribute the load.  

Or I'm wondering if there is some way to put a trigger on
every database which is being mirrored, so that every
transaction against the db that inserted or updated a
record was logged and simultaneously run against the mirror
data sets on the remote hosts.  

Has anyone done something like this before?  Any clues on
potential strategies would be appreciated.  

-- 
Hugh Esco 
RCK Computer Services 
http://reclaimedcomputers.ca/