Ask the Expert

Using RAC to aid performance

We are considering the use of RAC to aid performance in the sense that we wish to configure the various instances for different purposes (i.e. one for OLTP, one for batch, one for OLAP, etc.). Can you comment on some of the advantages or disadvantages of such an approach?

    Requires Free Membership to View

Before Real Application Clusters (RAC) there was Oracle Parallel Server (OPS). Actually, it was Cache Fusion that changed the whole picture and that appeared in OPS with Oracle 8.1.6, but it is Cache Fusion that makes RAC the great product it is today. Before Cache Fusion, OPS had a problem when two different instances needed access to the same data block. OPS had to make sure that the first instance wrote the block contents back to disk before the second instance could read that data. This is known as "disk pinging." Disk pinging could kill an application's performance even though multiple servers were involved in the database cluster. In those days, one way to avoid disk pinging was to segregate the application functionality among the instances in the OPS cluster. So having one instance for OLTP, one for batch, and one for OLAP in your RAC deployment is very similar to the application segregation that DBAs did in the old OPS days. I currently have two systems which we are investigating clustering with RAC. When we do, we will still do something akin to application segregation, but still enjoy other benefits of RAC. So I don't see anything wrong with your approach. Just make sure that you configure your application for Transparent Failover so that when the OLTP instance goes down, OLTP transactions can continue.

This was first published in February 2004

There are Comments. Add yours.

 
TIP: Want to include a code block in your comment? Use <pre> or <code> tags around the desired text. Ex: <code>insert code</code>

REGISTER or login:

Forgot Password?
By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy
Sort by: OldestNewest

Forgot Password?

No problem! Submit your e-mail address below. We'll send you an email containing your password.

Your password has been sent to: