Database Reference
In-Depth Information
1.
Architecting and implementing the storage solution. Since shared storage is required by
the RAC infrastructure, many IT departments use SAN (Storage Area Network) storage
for the RAC Database, as it can be accessed by multiple hosts through the storage
network. The reality is that a big SAN storage may be also shared by many different
applications. The storage administrator and the DBA need to work together to make sure
the storage requirements of the RAC Database are met. Some key areas for storage design
include storage network protocol, the topology of the physical network connections
among the RAC node hosts, and storage, storage capacity, and I/O load balance among
the applications that share the same storage.
2.
Provisioning storage volumes in the shared storage for the Oracle RAC Databases. At the
very least, you need to provision the storage volume for OCR and the voting disk files
and the volumes for the database files. The goal is to ensure that these volumes meet the
high availability and I/O performance and capacity requirements of the RAC Database
with the optimal design and configuration of these storage volumes, including the RAID
configuration of the volume; the capacity and number of disk spindles and what kind of
disks (speed of disks) form the storage volume; and the storage controller to which the
storage volume should be assigned.
3.
Making the storage volumes accessible to the RAC nodes. This includes configuring the
logical network connections to the storage volumes and presenting the storage volumes as
OS devices in all the RAC nodes.
4.
Creating Automatic Storage Management (ASM) diskgroups on the storage volumes for
OCR and voting disk files of the Oracle Clusterware.
5.
Creating ASM diskgroups for database files and optional ASM Cluster File System (ACFS)
for non-Oracle Database files such as Oracle RAC home and clusterfile system for other
applications.
6.
Ongoing maintenance tasks such as monitoring database I/O performance and identifying
storage I/O issues and performing storage reconfiguration, upgrade, or migration tasks.
In the preceding task list, tasks 1 and 2 are usually completed by the storage administrator and the OS system
administrator with input from the Oracle DBA. Task 3 is performed by the OS system administrator with input from
the Oracle DBA. Tasks 4-6 are traditionally the Oracle DBA's responsibility. In many IT organizations, especially
smaller IT departments, these responsibilities are combined and performed by one system administrator or DBA.
This chapter covers some of the techniques and best practices that are used for shared storage design and
configuration of the RAC Database, with a focus on how to meet the special storage requirements for the Oracle
Clusterware and RAC Database. These topics will be covered in this chapter:
•
Shared architecture and configuration for RAC
•
ASM
•
Storing OCR and voting disk files in ASM
•
ACFS
Storage Architecture and Configuration for Oracle RAC
In the Oracle RAC Database cluster, the cluster nodes connect directly to the same storage array where the critical
components of the Oracle Clusterware OCR and voting disk files and the database files are stored. The availability
of the storage array for each cluster node and the I/O performance of the storage array are critical to the Oracle
