Points to Note Before Installing Oracle

The following sections discuss some important tasks that need to be noted before you install Oracle in a VCS cluster on HP-UX.

Location of the $ORACLE_HOME

You can install the Oracle home directory ($ORACLE_HOME), which contains the Oracle binaries and configuration files, locally on each server's disk. Alternatively, you can place the Oracle home directory on the shared storage. The correct location for Oracle binaries depends on your environment. The following points discuss the advantages of each approach.

$ORACLE_HOME Directory on Shared Disks

When the Oracle Database Server ($ORACLE_HOME) is installed on shared disks, each cluster system must have the same mount point directory for the shared file system. Placing Oracle binaries on shared storage simplifies setting up a given system in a cluster to run an instance. Each database service group is self-contained. An instance can be moved to a new server in the cluster that shares the storage.

For example, in a four-system cluster, it is possible to have three database instances, or service groups, each at a different version of Oracle. If the Oracle binaries are placed on shared storage, three copies of Oracle, that is, one per version are required on shared storage. By contrast, placing the binaries on local storage, would require as many as 12 copies of the binaries (three versions on four systems).

The disadvantage of this approach is that a rolling upgrade of binaries on shared storage is not possible.

$ORACLE_HOME Directory on the Local Disk

Installing $ORACLE_HOME on the local disk has the advantage of allowing an upgrade of the Oracle database server running on an offline system while the database server runs on another system. The database server can later be switched to the upgraded system (provided the database is compatible), permitting a minimum amount of downtime.

The disadvantage of this approach is that with a large number of systems, it becomes difficult to maintain the various Oracle installations.

Multiple Oracle Instances (SIDs)

If multiple Oracle instances are defined in a single cluster configuration, the startup profile for each instance must be accessible on all systems listed in the service group's SystemList attribute.

Location of Database Tablespaces

If the tablespaces are created using regular (UFS or VxFS) files, the file systems containing these files must be located on shared disks. Create the same file system mount points on each system.

If you are using raw devices on shared disks for Oracle tablespaces, change the ownership to Oracle dba user and the permissions, or access mode, to 660 on the raw devices storing the Oracle data.

For example, if you are using VERITAS Volume Manager, type:

Transparent Listener Failover

To enable Oracle Server clients to reconnect after a system switch without reconfiguring, include at least one IP resource in the service group for the Oracle resource. The hostname mapping the IP address of this resource must be used for the Host field in the file $TNS_ADMIN/listener.ora.

If you are using the TCP/IP protocol for Oracle client/server communication, verify that the file /etc/services on each system defined in the service group's SystemList attribute contains entries for the service name of the Oracle Net Service.

Long Pathname Limitation for $ORACLE_HOME

The HP-UX process table limits process pathnames to 79 characters. The full pathname of processes in $ORACLE_HOME can possibly have 80 characters or more. In this case, you can create a soft link to the $ORACLE_HOME directory and use it in place of the long filename in the Home attribute in the main.cf file. You must create the link on each of the systems in the cluster.

1. Create a soft link to the long pathname. For example:
      # ln -s /opt/apps/oracle/home/directory/is/longer/than     
       /eighty/characters/oracle /opt/link_to_longpath
2. In the file /etc/VRTSvcs/conf/config/main.cf, modify the Home and Pfile attributes for both the Oracle resource type and the Netlsnr resource type (refer to the Sample Configuration in Sample Configurations).

   For example:

   
      Home = "/opt/link_to_longpath"
      Pfile = "/opt/link_to_longpath/dbs/initVRT.ora"

Defining NLS Information

You can define NLS information by defining the appropriate parameters in the Oracle parameter file or by defining the appropriate environment variables in the EnvFile. See the description of the EnvFile attribute in Resource Type Definitions.

Defining parameters in the Oracle parameters file affects NLS settings for the Oracle server. Defining environment variables affects the NLS input and output of client utilities.

Hot Backup of Oracle Database and VCS

If a cluster node fails while running a hot backup of an Oracle database, the failover to another node can succeed only if the Oracle resource attribute, AutoEndBkup, is set to a non-zero value. See Resource Type Definitions for more information about the Oracle agent attributes.

Otherwise, the database in the backup mode on the failover system cannot be opened and VCS cannot online the Oracle resource group.

The following errors are displayed to indicate this condition:

or

Before VCS can online the Oracle resource group on the failover system, you must take the datafiles in the database out of the backup mode and shut down the database so that it can be reopened. Refer to the Oracle documentation for instructions on how to change the state of the database files.