Support of Oracle RAC ASM with SGeRAC, January 2008

HP Availability Clusters Solutions Lab 1/25/2008 Page 2

Introduction

This document discusses the use of the Oracle 10g Release 2 (10g R2) and11g Release 1 (11g R1)

database server feature called Automatic Storage Management (ASM) in configurations of HP

Serviceguard Extension for Real Application Clusters (SGeRAC).

We begin with a brief review of ASM - its functionality, pros and cons, and method of operation.

Then we look in detail at how we configure ASM with SGeRAC (version A.11.17 or later is required).

ASM Background

What is Automatic Storage Management (ASM)?

ASM was introduced by Oracle in 10g as a component of the Oracle database and provides an

alternative to platform file systems and volume managers for the management of most file types used

to store the Oracle database, including Oracle datafiles, control files, and online and archived redo

log files. (The full list of types of files supported by ASM can be found in the section What Types of

Files Does ASM Support? in Chapter 12, Using Automatic Storage Management of Oracle®

Database Administrator’s Guide 10g R2

or in the section About ASM Files Chapter 1, Introduction to

Automatic Storage Management (ASM) of Storage Administrator’s Guide

.) File types not supported

by ASM include Oracle database server binaries, trace files, audit files, alert logs, backup files,

export files, tar files, core files, as well as the quorum and registry devices used by Oracle

Clusterware. Storage for application binaries and data cannot be managed by ASM.

For the supported file types, ASM provides file management services and takes care of mirroring and

striping these files. ASM ensures I/O distribution over available disks through its striping capability

and it supports online disk addition and deletion.

A major advantage of ASM is the ease of management it provides for database files:

• The system administrator has only to specify the set of raw devices to be used in an ASM disk

group; the tasks of configuring and administering volume/disk groups and file systems are

eliminated. Oracle ASM makes use of the Oracle feature called Oracle-managed files

and

performs the tasks of creating, deleting and extending files on behalf of database instances;

additionally, it manages their mirroring and striping.

• If a device is added to, or deleted from, an ASM disk group, ASM automatically rebalances

database file striping based on the new disk layout.

Figure 1 contrasts the Oracle storage hierarchy as it appears when platform or 3rd party volume

managers and file systems are used for Oracle data files, compared to when ASM is used. The layers

corresponding to file systems and volume managers are absorbed into ASM. The files and directories

in the storage hierarchy are not visible using standard operating system commands; to display them

the customer must use Oracle utilities.

See http://www.oracle.com/pls/db102/portal.portal_db?selected=4) → Guides → Administrator's Guide

See http://www.oracle.com/pls/db111/portal.portal_db?selected=4&frame= → Storage → Storage Administrator's Guide