Veritas Storage Foundation 5.0 for Oracle RAC Configuration Guide Extracts for HP Serviceguard Storage Management Suite, Second Edition, May 2008

Introducing Serviceguard Extension for RAC

Communication Infrastructure

Chapter 1

Communication Infrastructure

To understand the communication infrastructure, review the data flow and

communication requirements.

Data Flow

The CVM, CFS, ODM, and Oracle Real Application Clusters (RAC) elements reflect the

overall data flow, or data stack, from an instance running on a server to the shared

storage. The various Oracle processes composing an instance—such as DB Writers, Log

Writer, Checkpoint, Archiver, and Server—read and write data to the storage through

the I/O stack in the diagram. Oracle communicates through the ODM interface to CFS,

which in turn accesses the storage through the CVM.

Figure 1-2 Data Stack

Oracle

RAC

Instance

Oracle

RAC

Instance

LGWR

ARCH

CKPT

DBWR

ODM ODM

CFSCFS

CVM CVM

Redo

Log

Files