Re: Symetric Replication Anyone?

Mike Lacey wrote:
>
> What experiences do people have with Symetric
> Replication?
>
> This is what I'm considering:
>
> Central site with with an rs6000 running Oracle
> V7.2.6.0.2
>
> Remote sites (currently with horrible performance
> problems) connected via a 64k leased line with NW
> 3.12 servers running Oracle 7.something.
>
> Some tables would be replicated at the remote
> sites.
>
> I've not "done" replication before and I'd value
> everyones comments.

I'm currently involved in a project that involves a master site, a backup master site, and several (24) snapshot sites. Here's just a few issues off the top of my head:

1. On your master database, put as much memory as you can. Then try to get some more. Seriously, with all these sites, we experienced a multitude of memory problems with the system swapping continuously. The more sites you add, the busier your system is going to be.
2. Plan your database carefully, especially your snapshot sites, and your update times. We are currently running with a 5 minute update on some tables and 30 second updates on others.
3. If you are running archive log on your master database, be prepared to allocate a lot of disk space. Our log switch rate on a database that is currently doing NOTHING is about once every 3-5 minutes.
4. As much as Oracle would like it to be, the replication system is not trivial, and you will need to study the manuals carefully. There are a lot of stored procedures, etc. that need to be run to set up your replicated schema. The Replication Manager in the Oracle Enterprise Manager pack is a step in the right direction, but it still is limited. Plus, as in any Oracle manual, procedures don't always look/act the way they're advertised.
5. If you can, upgrade to the most version of Oracle (7.3). There were known replication problems in 7.2. If/When you do upgrade, make sure you link in the Spatial Data Option, as there was a problem with 7.3 using database links, and that was the work-around.

Oracle replication works surprisingly well when it is all up and running, but just be careful in what you do! Received on Thu Oct 17 1996 - 00:00:00 CEST