Replication

I'm engaged in a project where replication is required. The specs define 3 master databases connected with dedicated lines. Downtime is not permited ( well, almost ), and each local comunity should connect to his local server if it's up and running. In case of failure of the local server, a remote server will take his place.

We evaluating Oracle's Advanced Replication Option in Multiple Masters async configuration. Sync could be used but there's no faith on the performance.

Can't estimate, so early, the transaction rate at each site but it will be a standard OLTP system with about 20 users at each site and between 50 and 100 tables.

Ower concerns are ( for now ) :

1) performance ( most important issue !? )
2) maintenence of the system
3) Implementation insights on recovery situations.

A great concern on point 3, is what should be done with not-yet-replicated-data. If a server crashes and the commited data is not replicated on the other servers, the show must go on and data will be reentered on the new server ( remote ). Suposing the replication has 10 min delay, we would loose about 20 minutes in the process.

Ok. That's acceptable. But now the crashed server comes up again, and tries to push non-replicated data to the other servers. Disaster !!!

Any comments on this will be much appreciated, specially from experiences with similar systems/architectures, namely the usability of Oracle's Replication architecture.

Thanks

• Jorge Agra

PS : for direct mail reply cut the please_no_spam from my email address. Received on Fri Feb 06 1998 - 00:00:00 CST