A unique Oracle database feature is Real Application Clusters (RAC). RAC allows multiple database servers to work on the same database simultaneously, improving scalability and fault tolerance.
Both of these features have the potential to drop your operating costs: RAC allows you to use a cluster of inexpensive servers instead of a single massive SMP box, and ASM allows you to use a cluster of inexpensive disks instead of a single massive disk array.
RAC & ASM for E-Business Suite Users
Here’s where things get interesting for E-Business Suite users: E-Business Suite Release 11i is certified with 9i RAC, 10gR1 RAC & ASM and 10gR2 RAC & ASM.
As an aside, we use 10gR1 RAC with our own E-Business Suite Release 11i instance for Oracle’s corporate Global Single Instance. We’re planning an upgrade to 10gR2 in the near future.
Initially Awkward with 10gR1
This is all good, but our first version of the E-Business Suite certification with 10gR1 RAC and ASM had an awkward restriction. To use this combination, you first had to migrate your E-Business Suite environment to RAC. After that was done, you could then migrate your RAC environment to ASM.
There were very good technical reasons for doing things this way, but no matter. This proved to be really problematic for customers who decided to take advantage of ASM long before they even considered switching to RAC.
Awkward No Longer
We have a small but brilliant team working in this area and they have managed to lift that restriction for E-Business Suite users. With the latest version of the 10gR1 RAC & ASM Installation Guide, you can now do this in any order you’d like: RAC then ASM, or ASM then RAC.
This restriction doesn’t exist with our 10gR2 certification, so DBAs who waited for that certification can use RAC and ASM in any order today.