Testing for Scalability - Expert Oracle RAC Performance Diagnostics and Tuning - page 87

■ Note services and load-balancing features are covered in Chapter 15.

Scalable Components
Scalability of the RAC configuration depends on the scalability of components that comprise the RAC cluster. A RAC
system effectively extends the local buffer cache and can therefore reduce the amount of physical I/O. Cache data
transfers via the interconnect allow low latency access. This at the outset makes the interconnect as the primary
component for scalability. As illustrated in Figure 4-2 , RAC has seven components that can affect the overall
performance of the database if not configured correctly.

1

2

Node 1 Node 2 Node 3 Node 4 Node 5 Node 6

3

SSKY_1 SSKY_2 SSKY_3 SSKY_4 SSKY_5 SSKY_6

5

4

6

AV7 AV8 AVL9 AV10 AV11 AV12 AV13 AV14 AV15 AV16 AV17 AV18

GRID_DATA PRD_DATA PRD_FRA

Figure 4-2. Scalable components in a RAC configuration

Interconnect
This is the backbone of the RAC architecture: data movement and sharing between instances in the cluster happen via
the cluster interconnect.