hi,

Can there be module that replicates or updates the remote db based on the contents of db used by xoops. So that at any given time if one db goes down or one system goes down the other one can be used instantly.

not a module, but there are several resources online about mySQL clustring:

Prometheus mySQL clustering project
MySQL 4.1 (in beta) to support clustering

Then there is database replication which is needs a manual rollover to the slave databases.

Replication in mySQL

Be warned - setting up these types of architectures are not for the faint of heart, and my not be feasible if you are in a shared hosting environment.

ya i have a fare bit of idea in regard to this. And on shared hosting its not possible directly thats why i was looking for some sort of module in xoops. Which performs following things..

1. Maintains data diff on a given timescale using MySQL built in fucntions.

2. connecting to remote db and uploading that data.

this would become a bit resource hungry as well as bandwidth killer. But then in anycase of database clustering this is gonna happen only thing is how well the resources can be managed.