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Oracle® Database Oracle Clusterware and Oracle Real Application Clusters Installation Guide
10g Release 2 (10.2) for hp Tru64

Part Number B14206-02
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3 Configuring Oracle Clusterware and Oracle Database Storage

This chapter describes the storage configuration tasks that you must complete before you start Oracle Universal Installer. It includes information about the following tasks:

3.1 Reviewing Storage Options for Oracle Clusterware, Database, and Recovery Files

This section describes supported options for storing Oracle Clusterware files, Oracle Database files, and data files.

3.1.1 Overview of Oracle Clusterware Storage Options

There are three ways of storing Oracle Clusterware files:

  • A supported shared file system: Supported file systems include the following:

    • Cluster File System with TruCluster v. 5.1B with Advanced File System (AdvFS)

  • Raw partitions: Raw partitions are disk partitions that are not mounted and written to using the file system, but instead are accessed directly by the application.

  • Logical Storage Manager with TruCluster v. 5.1B

Note:

Tru64 UNIX NFS V2 is not supported with Oracle Real Application Clusters.

3.1.2 Overview of Oracle Database and Recovery File Options

There are three ways of storing Oracle Database and recovery files:

  • Automatic Storage Management: Automatic Storage Management (ASM) is an integrated, high-performance database file system and disk manager for Oracle Database files.

  • A supported shared file system: Supported file systems include the following:

    • HP Tru64 TruCluster

  • Raw partitions (database files only): A raw partition is required for each database file.

See Also:

For information about certified compatible storage options, refer to the Oracle Storage Compatibility Program (OSCP) Web site, which is at the following URL:

http://www.oracle.com/technology/deploy/availability/htdocs/oscp.html

3.1.3 General Storage Considerations

For all installations, you must choose the storage option that you want to use for Oracle Clusterware files and Oracle Database files. If you want to enable automated backups during installation, then you must also choose the storage option that you want to use for recovery files (the flash recovery area). You do not have to use the same storage option for each file type.

3.1.3.1 TruCluster Cluster File System

On V5.1B systems and higher, Oracle requires using the HP Tru64 TruCluster Cluster File Systems (CFS). TruCluster provides a single namespace file system for all nodes in a cluster. All file systems mounted in a cluster are automatically seen by all nodes in the cluster. Because it is layered on top of the AdvFS file system, the TruCluster file system inherits much of the characteristics of non-clustered systems.

The TruCluster file system supports a concurrent direct I/O model. Any node that has physical connectivity to a drive can issue data I/O to its file systems without consulting with the owning node. However, all metadata changes to a file (for example, extending, closing, changing the access or modification date) are still served by the owner node and can still cause cluster interconnect saturation. Therefore, it is possible for the CREATE TABLESPACE, ALTER TABLESPACE, ADD DATAFILE, ALTER DATABASE DATAFILE, or RESIZE commands to perform poorly on a CFS file system when compared to raw devices.

3.1.3.2 Direct I/O and Oracle Real Application Clusters

If you use the TruCluster file system for Oracle Real Application Clusters data file storage, then you must enable Direct I/O on your system. The disks that use the TruCluster file system must be physically connected to all computers running the Oracle instances, including disks attached by fiber channel. It excludes cases where I/O must be served by another node because of physical connectivity.

3.1.3.3 Voting Disk File Placement

For voting disk file placement, ensure that each voting disk is configured so that it does not share any hardware device or disk, or other single point of failure. An absolute majority of voting disks configured (more than half) must be available and responsive at all times for Oracle Clusterware to operate.

3.1.3.4 Single-Instance Systems Using Oracle Clusterware

For single-instance Oracle Database installations using Oracle Clusterware for failover, if you do not want the failover processing to include dismounting and remounting disks, then you must use ASM, or shared raw disks.

3.1.3.5 Selecting Storage Options

The following table shows the storage options supported for storing Oracle Clusterware files, Oracle Database files, and Oracle Database recovery files. Oracle Database files include data files, control files, redo log files, the server parameter file, and the password file. Oracle Clusterware files include the Oracle Cluster Registry (OCR), a mirrored OCR file (optional), the Oracle Clusterware voting disk, and additional voting disk files (optional).

Note:

For the most up-to-date information about supported storage options for RAC installations, refer to the Certify pages on the OracleMetaLink Web site:
http://metalink.oracle.com

Table 3-1 Supported Storage Options for Oracle Clusterware, Database, and Recovery Files

Storage Option File Types Supported
OCR and Voting Disks Oracle Software Database Recovery

Automatic Storage Management

No

No

Yes

Yes

Cluster File System with TruCluster v.5.1B

Yes

Yes

Yes

Yes

Logical Storage Manager with TruCluster v. 5.1B

Voting Disks only

Yes

Yes

No

Shared raw partitions

Voting Disks only

No

Yes

No


Use the following guidelines when choosing the storage options that you want to use for each file type:

  • You can choose any combination of the supported storage options for each file type provided that you satisfy all requirements listed for the chosen storage options.

  • Oracle recommends that you choose Automatic Storage Management (ASM) as the storage option for database and recovery files.

  • The Oracle Cluster Registry must be stored on a cluster file system. A shared Logical Storage Manager volume or shared disk partition is not a supported storage option for the OCR.

  • For Standard Edition RAC installations, ASM is the only supported storage option for database or recovery files.

  • You cannot use ASM to store Oracle Clusterware files, because these files must be accessible before any ASM instance starts.

  • If you intend to use ASM with RAC, and you are configuring a new ASM instance, then your system must meet the following conditions:

    • All nodes on the cluster have the release 2 (10.2) version of Oracle Clusterware installed.

    • Any existing ASM instance on any node in the cluster is shut down.

  • If you intend to upgrade an existing RAC database, or a RAC database with ASM instances, then you must ensure that your system meets the following conditions:

    • Oracle Universal Installer (OUI) and Database Configuration Assistant (DBCA) are run on the node where the RAC database or RAC database with ASM instance is located.

    • The RAC database or RAC database with an ASM instance is running on the same nodes that you intend to make members of the new cluster installation. For example, if you have an existing RAC database running on a three-node cluster, then you must install the upgrade on all three nodes. You cannot upgrade only 2 nodes of the cluster, removing the third instance in the upgrade.

    See Also:

    Oracle Database Upgrade Guide for information about how to prepare for upgrading an existing database
  • If you do not have a storage option that provides external file redundancy, then configure additional storage areas to provide voting disk redundancy, either as storage areas on the cluster file system, or three raw devices or logical volume manager areas. You must configure at least three voting disk areas. At least two voting disks must be available for Oracle Clusterware to operate.

3.1.4 After You Have Selected Disk Storage Options

When you have determined your disk storage options, you must perform the following tasks in the following order:

1: Check for available shared storage with CVU

Refer to Checking for Available Shared Storage with CVU.

2: Configure shared storage for Oracle Clusterware files

3: Configure storage for Oracle Database files and recovery files

3.2 Checking for Available Shared Storage with CVU

To check for all shared file systems available across all nodes on the cluster on a supported shared file system, use the following command:

/mountpoint/crs/Disk1/cluvfy/runcluvfy.sh comp ssa -n node_list

If you want to check the shared accessibility of a specific shared storage type to specific nodes in your cluster, then use the following command syntax:

/mountpoint/crs/Disk1/cluvfy/runcluvfy.sh comp ssa -n node_list -s storageID_list

In the preceding syntax examples, the variable mountpoint is the mountpoint path of the installation media, the variable node_list is the list of nodes you want to check, separated by commas, and the variable storageID_list is the list of storage device IDs for the storage devices managed by the TruCluster file system you want to check.

For example, if you want to check the shared accessibility from node1 and node2 of storage devices /dev/sdb and /dev/sdc, and your mountpoint is /dev/dvdrom/, then enter the following command:

/dev/dvdrom/crs/Disk1/cluvfy/runcluvfy.sh comp ssa -n node1,node2 -s /dev/sdb,/dev/sdc

Note:

On HP Tru64, only CFS shared storage checks are performed with CVU. Shared storage checks for LVM or raw disks are not performed, as these are not supported shared storage options.

3.3 Configuring Storage for Oracle Clusterware Files on a Supported Shared File System

Oracle Universal Installer (OUI) does not suggest a default location for the Oracle Cluster Registry (OCR) or the Oracle Clusterware voting disk. If you choose to create these files on a file system, then review the following sections to complete storage requirements for Oracle Clusterware files:

3.3.1 Requirements for Using a File System for Oracle Clusterware Files

To use a file system for Oracle Clusterware files, the file system must comply with the following requirements:

  • To use a cluster file system, it must be a supported cluster file system, as listed in the section "Deciding to Use a Cluster File System for Data Files".

  • If you choose to place your Oracle Cluster Registry (OCR) files on a shared file system, then one of the following must be true:

    • The disks used for the file system are on a highly available storage device, (for example, a RAID device that implements file redundancy).

    • At least two file systems are mounted, and use the features of Oracle Database 10g Release 2 (10.2) to provide redundancy for the OCR.

  • If you intend to use a shared file system to store database files, then use at least two independent file systems, with the database files on one file system, and the recovery files on a different file system.

  • The oracle user must have write permissions to create the files in the path that you specify.

Note:

If you are upgrading from Oracle9i release 2, then you can continue to use the raw device or shared file that you used for the SRVM configuration repository instead of creating a new file for the OCR.

Use Table 3-2 to determine the partition size for shared file systems.

Table 3-2 Shared File System Volume Size Requirements

File Types Stored Number of Volumes Volume Size

Oracle Clusterware files (OCR and voting disks) with external redundancy

1

At least 256 MB for each volume

Oracle Clusterware files (OCR and voting disks) with redundancy provided by Oracle software.

1

At least 256 MB for each volume

Redundant Oracle Clusterware files with redundancy provided by Oracle software (mirrored OCR and two additional voting disks)

1

At least 256 MB of free space for each OCR location, if the OCR is configured on a file system

or

At least 256 MB available for each OCR location if the OCR is configured on raw devices or block devices.

and

At least 256 MB for each voting disk location, with a minimum of three disks.

Oracle Database files

1

At least 1.2 GB for each volume

Recovery files

Note: Recovery files must be on a different volume than database files

1

At least 2 GB for each volume


In Table 3-2, the total required volume size is cumulative. For example, to store all files on the shared file system, you should have at least 3.4 GB of storage available over a minimum of two volumes.

3.3.2 Creating Required Directories for Oracle Clusterware Files on Shared File Systems

Use the following instructions to create directories for Oracle Clusterware files. You can also configure shared file systems for the Oracle Database and recovery files.

Note:

For cluster file system storage, you must complete this procedure only if you want to place the Oracle Clusterware files on a separate file system from the Oracle base directory.

To create directories for the Oracle Clusterware files on separate file systems from the Oracle base directory, follow these steps:

  1. If necessary, configure the shared file systems that you want to use and mount them on each node.

    Note:

    The cluster file system directory that you use for the file system must be identical on each node. Ensure that the file systems are configured to mount automatically when a node restarts.
  2. Use the df -h command to determine the free disk space on each storage area.

  3. From the display, identify the file systems that you want to use:

    File Type File System Requirements
    Oracle Clusterware files Choose a file system with at least 512 MB of free disk space (one OCR and one voting disk, with external redundancy)
    Database files Choose either:
    • A single file system with at least 1.2 GB of free disk space.

    • Two or more file systems with at least 1.2 GB of free disk space in total.

    Recovery files Choose a file system with at least 2 GB of free disk space.

    If you are using the same file system for more than one type of file, then add the disk space requirements for each type to determine the total disk space requirement.

  4. Note the names of the cluster file system directories for the file systems that you identified.

  5. If the user performing installation (typically, oracle) has permissions to create directories on the disks where you plan to install Oracle Clusterware and Oracle Database, then OUI creates the Oracle Clusterware file directory, and DBCA creates the Oracle Database file directory, and the Recovery file directory.

    If the user performing installation does not have write access, then you must create these directories manually using commands similar to the following to create the recommended subdirectories in each of the cluster file system (cfsdirectory) directories and set the appropriate owner, group, and permissions on them:

    • Oracle Clusterware file directory:

      # mkdir /cfsdirectory/oracrs
      # chown oracle:oinstall /cfsdirectory/oracrs
      # chmod 775 /cfsdirectory/oracrs
      
      
    • Database file directory:

      # mkdir /cfsdirectory/oradata
      # chown oracle:oinstall /cfsdirectory/oradata
      # chmod 775 /cfsdirectory/oradata
      
      
    • Recovery file directory (flash recovery area):

      # mkdir /cfsdirectory/flash_recovery_area
      # chown oracle:oinstall /cfsdirectory/flash_recovery_area
      # chmod 775 /cfsdirectory/flash_recovery_area
      
      

By making the oracle user the owner of these directories, this permits them to be read by multiple Oracle homes, including those with different OSDBA groups.

When you have completed creating subdirectories in each of the mount point directories, and set the appropriate owner, group, and permissions, you have completed TruCluster configuration.

3.4 Configuring Storage for Oracle Clusterware Files on Raw Devices

The following subsections describe how to configure Oracle Clusterware files on raw partitions.

3.4.1 Identifying Required Raw Partitions for Clusterware Files

Table 3-3 lists the number and size of the raw partitions that you must configure for Oracle Clusterware files.

Table 3-3 Raw Partitions Required for Oracle Clusterware Files

Number Size for Each Partition (MB) Purpose

2

(or 1, if you have external redundancy support for this file)

256

Oracle Cluster Registry

Note: You need to create these raw partitions only once on the cluster. If you create more than one database on the cluster, then they all share the same Oracle Cluster Registry (OCR).

You should create two partitions: One for the OCR, and one for a mirrored OCR.

If you are upgrading from Oracle9i release 2, then you can continue to use the raw device that you used for the SRVM configuration repository instead of creating this new raw device.

3

(or 1, if you have external redundancy support for this file)

256

Oracle Clusterware voting disks

Note: You need to create these raw partitions only once on the cluster. If you create more than one database on the cluster, then they all share the same Oracle Clusterware voting disk.

You should create three partitions: One for the voting disk, and two for additional voting disks.


Note:

Voting disk and OCR files requires at least 500 MB. The total size required depends on the number of nodes on the cluster.

3.4.2 Configuring Raw Devices

Caution:

Do not attempt to set up raw devices without the help of an experienced system administrator and specific knowledge about the system you are using.

To configure raw devices and volumes on Tru64 systems:

  1. If necessary, install or configure the shared disk devices that you intend to use for the raw partitions and restart the system.

    Ensure that the partitions you are adding are on a shared disk. You can store the files that Oracle Real Application Clusters requires directly on the cluster file system.

    Note:

    Because the number of partitions that you can create on a single device is limited, you might need to create the required raw partitions on more than one device.
  2. Determine the names of the free disk partitions.

    A free disk partition is one that is not used for a Tru64 file system that complies with the following restrictions:

    • It is not listed when you run the command /usr/sbin/mount.

    • It is not in use as a swap device.

    • It does not overlap a swap partition.

    • It is not in use by other Tru64 applications.

    • It does not overlap the Tru64 file system.

    • It does not use a space already used by the file system.

    To determine if a partition is free, obtain a complete map of the starting locations and sizes of the partitions on the device and check for free space. Some partitions may contain file systems that are currently not mounted and are not listed in the /usr/sbin/mount output.

    Note:

    Ensure that the partition does not start at cylinder 0.
  3. Set up the raw device for use by Oracle Clusterware.

    Begin by verifying that the disk is partitioned. If it is not, then use the command disklabel to partition it.

  4. Enter the ls command to view the owner and permissions of the device file. For example:

    $ ls -1a
    
    
  5. Ensure that the partition is owned by the oracle user. If necessary, use the command chown to change the ownership on the block and character files for the device. For example:

    # chown oracle /dev/rdisk/dsk10c
    
    
  6. Ensure that the partition has the correct permissions. If necessary, use the command chmod to make the partition accessible only to the oracle user. For example:

    # chmod 600 /dev/rdisk/dsk10c
    
    
  7. Create a symbolic link to the raw devices you require. For example:

    $ ln -s /dev/rdisk/dsk10c /oracle_data/datafile.dbf
    
    

    To verify that you have created the symbolic link, use the character special device (not the block special device) and enter the following command:

    $ ls -Ll datafile
    
    

    The following message should appear:

    crwxrwxrwx oracle dba datafile
    
    

3.4.3 Completing Supported Shared Storage Configuration

When you have completed creating subdirectories in each of the mount point directories, and set the appropriate owner, group, and permissions, you have completed supported shared storage configuration.

3.5 Choosing a Storage Option for Oracle Database Files

Database files consist of the files that make up the database, and the recovery area files. There are five options for storing database files:

During configuration of Oracle Clusterware, if you configure TruCluster logical volumes large enough to hold the database files and recovery files, and you do not plan to use ASM, then you have completed required pre-installation steps. You can proceed to Chapter 4, "Installing Oracle Clusterware".

If you want to place your database files on ASM, then proceed to Configuring Disks for Automatic Storage Management.

If you want to place your database files on raw devices, and manually provide storage management for your database and recovery files, then proceed to "Configuring Database File Storage on Raw Devices".

Note:

Databases can consist of a mixture of ASM files and non-ASM files. Refer to Oracle Database Administrator's Guide for additional information about ASM.

3.5.1 Deciding to Use a Cluster File System for Data Files

If you choose to place the Oracle database files on a file system, then use the following guidelines when deciding where to place them:

  • You must choose a shared file system on shared disk; the file system must be a cluster file system.

  • The default path suggested by the Installer for the database file directory is a subdirectory of the Oracle base directory. You can choose this path only if you are using an Oracle base directory that is on a shared file system.

    This default location is not recommended for production databases.

  • You can choose either a single file system or more than one file system to store the database files:

    • If you want to use a single file system, choose a file system on a physical device that is dedicated to the database.

      For best performance and reliability, choose a RAID device or a logical volume on more than one physical device and implement the stripe-and-mirror-everything (SAME) methodology.

    • If you want to use more than one file system, choose file systems on separate physical devices that are dedicated to the database.

      This method enables you to distribute physical I/O and create separate control files on different devices for increased reliability. It also enables you to fully implement the OFA guidelines. You must choose either the Advanced database creation option or the Custom installation type during the installation to implement this method.

  • If you intend to create a preconfigured database during the installation, the file system (or file systems) that you choose must have at least 1.2 GB of free disk space.

    For production databases, you must estimate the disk space requirement depending on the use that you want to make of the database.

  • For optimum performance, the file systems that you choose should be on physical devices that are used only by the database.

  • The oracle user must have write permissions to create the files in the path that you specify.

3.5.2 Guidelines for Placing Oracle Recovery Files on a File System

Note:

You must choose a location for recovery files only if you intend to enable automated backups during the installation.

If you choose to place the Oracle recovery files on a file system, use the following guidelines when deciding where to place them:

  • To prevent disk failure from making both the database files and the recovery files unavailable, place the recovery files in a file system on a different physical disk from the database files.

    Note:

    Alternatively use an ASM disk group with a normal or high redundancy level for either or both file types.
  • The file system that you choose should have at least 2 GB of free disk space.

    The disk space requirement is the default disk quota configured for the flash recovery area (specified by the DB_RECOVERY_FILE_DEST_SIZE initialization parameter).

    If you choose the Custom installation type or the Advanced database configuration option, you can specify a different disk quota value. After you create the database, you can also use Oracle Enterprise Manager Grid Control or Database Control to specify a different value.

    For more information about sizing the flash recovery area, refer to the Oracle Backup and Recovery Basics manual.

  • You must use TruClusters.

  • The default path suggested by the Installer for the flash recovery area is a subdirectory of the Oracle base directory. You can choose this path only if you are using an Oracle base directory that is on a shared file system.

    This default location is not recommended for production databases.

  • The oracle user must have write permissions to create the files in the path that you specify.

3.6 Configuring Disks for Automatic Storage Management

This section describes how to configure disks for use with Automatic Storage Management. Before you configure the disks, you must determine the number of disks and the amount of free disk space that you require. The following sections describe how to identify the requirements and configure the disks:

Note:

For Automatic Storage Management installations:
  • Although this section refers to disks, you can also use zero-padded files on a certified NAS storage device in an Automatic Storage Management disk group. Refer to Oracle Database Installation Guide for hp Tru64 for information about creating and configuring NAS-based files for use in an Automatic Storage Management disk group.

  • You can run ASM using ASMLIB, or run ASM using raw partitions.

3.6.1 Identifying Storage Requirements for Automatic Storage Management

To identify the storage requirements for using Automatic Storage Management, you must determine how many devices and the amount of free disk space that you require. To complete this task, follow these steps:

  1. Determine whether you want to use Automatic Storage Management for Oracle Database files, recovery files, or both.

    Note:

    You do not have to use the same storage mechanism for database files and recovery files. You can use the file system for one file type and Automatic Storage Management for the other.

    If you choose to enable automated backups and you do not have a shared file system available, then you must choose Automatic Storage Management for recovery file storage.

    If you enable automated backups during the installation, you can choose Automatic Storage Management as the storage mechanism for recovery files by specifying an Automatic Storage Management disk group for the flash recovery area. Depending on how you choose to create a database during the installation, you have the following options:

    • If you select an installation method that runs Database Configuration Assistant in interactive mode (for example, by choosing the Advanced database configuration option) then you can decide whether you want to use the same Automatic Storage Management disk group for database files and recovery files, or use different disk groups for each file type.

      The same choice is available to you if you use Database Configuration Assistant after the installation to create a database.

    • If you select an installation method that runs Database Configuration Assistant in noninteractive mode, then you must use the same Automatic Storage Management disk group for database files and recovery files.

  2. Choose the Automatic Storage Management redundancy level that you want to use for the Automatic Storage Management disk group.

    The redundancy level that you choose for the Automatic Storage Management disk group determines how Automatic Storage Management mirrors files in the disk group and determines the number of disks and amount of free disk space that you require, as follows:

    • External redundancy

      An external redundancy disk group requires a minimum of one disk device. The effective disk space in an external redundancy disk group is the sum of the disk space in all of its devices.

      Because Automatic Storage Management does not mirror data in an external redundancy disk group, Oracle recommends that you use only RAID or similar devices that provide their own data protection mechanisms as disk devices in this type of disk group.

    • Normal redundancy

      In a normal redundancy disk group, Automatic Storage Management uses two-way mirroring by default, to increase performance and reliability. A normal redundancy disk group requires a minimum of two disk devices (or two failure groups). The effective disk space in a normal redundancy disk group is half the sum of the disk space in all of its devices.

      For most installations, Oracle recommends that you select normal redundancy disk groups.

    • High redundancy

      In a high redundancy disk group, Automatic Storage Management uses three-way mirroring to increase performance and provide the highest level of reliability. A high redundancy disk group requires a minimum of three disk devices (or three failure groups). The effective disk space in a high redundancy disk group is one-third the sum of the disk space in all of its devices.

      While high redundancy disk groups do provide a high level of data protection, you should consider the greater cost of additional storage devices before deciding to select high redundancy disk groups.

  3. Determine the total amount of disk space that you require for the database files and recovery files.

    Use the following table to determine the minimum number of disks and the minimum disk space requirements for installing the starter database:

    Redundancy Level Minimum Number of Disks Database Files Recovery Files Both File Types
    External 1 1.15 GB 2.3 GB 3.45 GB
    Normal 2 2.3 GB 4.6 GB 6.9 GB
    High 3 3.45 GB 6.9 GB 10.35 GB

    For RAC installations, you must also add additional disk space for the Automatic Storage Management metadata. You can use the following formula to calculate the additional disk space requirements (in MB):

    15 + (2 * number_of_disks) + (126 * number_of_Automatic_Storage_Management_instances)

    For example, for a four-node RAC installation, using three disks in a high redundancy disk group, you require an additional 525 MB of disk space:

    15 + (2 * 3) + (126 * 4) = 525

    If an Automatic Storage Management instance is already running on the system, then you can use an existing disk group to meet these storage requirements. If necessary, you can add disks to an existing disk group during the installation.

    The following section describes how to identify existing disk groups and determine the free disk space that they contain.

  4. Optionally, identify failure groups for the Automatic Storage Management disk group devices.

    Note:

    You need to complete this step only if you intend to use an installation method that runs Database Configuration Assistant in interactive mode, for example, if you intend to choose the Custom installation type or the Advanced database configuration option. Other installation types do not enable you to specify failure groups.

    If you intend to use a normal or high redundancy disk group, then you can further protect your database against hardware failure by associating a set of disk devices in a custom failure group. By default, each device comprises its own failure group. However, if two disk devices in a normal redundancy disk group are attached to the same SCSI controller, then the disk group becomes unavailable if the controller fails. The controller in this example is a single point of failure.

    To protect against failures of this type, you could use two SCSI controllers, each with two disks, and define a failure group for the disks attached to each controller. This configuration would enable the disk group to tolerate the failure of one SCSI controller.

    Note:

    If you define custom failure groups, then you must specify a minimum of two failure groups for normal redundancy disk groups and three failure groups for high redundancy disk groups.
  5. If you are sure that a suitable disk group does not exist on the system, then install or identify appropriate disk devices to add to a new disk group. Locate appropriate disk devices with the following command:

    # hwmgr -view devices
    # df -k
    
    

    When you select Automatic Storage Management (ASM), OUI displays an ASM Management Options page showing the disk partition locations from which you must select. The default partitions are in the following path:

    /dev/rdisk/*
    
    

    Use the following guidelines when identifying appropriate disk devices:

    • All of the devices in an Automatic Storage Management disk group should be the same size and have the same performance characteristics.

    • Do not specify more than one partition on a single physical disk as a disk group device. Automatic Storage Management expects each disk group device to be on a separate physical disk.

    • Although you can specify a logical volume as a device in an Automatic Storage Management disk group, Oracle does not recommend their use. Logical volume managers can hide the physical disk architecture, preventing Automatic Storage Management from optimizing I/O across the physical devices. They are not supported with RAC.

    See Also:

    The "Configuring Disks for Automatic Storage Management" section for information about completing this task

3.6.2 Using an Existing Automatic Storage Management Disk Group

If you want to store either database or recovery files in an existing Automatic Storage Management disk group, then you have the following choices, depending on the installation method that you select:

  • If you select an installation method that runs Database Configuration Assistant in interactive mode (for example, by choosing the Advanced database configuration option), then you can decide whether you want to create a disk group, or to use an existing one.

    The same choice is available to you if you use Database Configuration Assistant after the installation to create a database.

  • If you select an installation method that runs Database Configuration Assistant in noninteractive mode, then you must choose an existing disk group for the new database; you cannot create a disk group. However, you can add disk devices to an existing disk group if it has insufficient free space for your requirements.

Note:

The Automatic Storage Management instance that manages the existing disk group can be running in a different Oracle home directory.

To determine if an existing Automatic Storage Management disk group exists, or to determine if there is sufficient disk space in a disk group, you can use Oracle Enterprise Manager Grid Control or Database Control. Alternatively, you can use the following procedure:

  1. View the contents of the oratab file to determine if an Automatic Storage Management instance is configured on the system:

    $ more /etc/oratab
    
    

    If an Automatic Storage Management instance is configured on the system, then the oratab file should contain a line similar to the following:

    +ASM2:oracle_home_path
    
    

    In this example, +ASM2 is the system identifier (SID) of the Automatic Storage Management instance, with the node number appended, and oracle_home_path is the Oracle home directory where it is installed. By convention, the SID for an Automatic Storage Management instance begins with a plus sign.

  2. Set the ORACLE_SID and ORACLE_HOME environment variables to specify the appropriate values for the Automatic Storage Management instance that you want to use.

  3. Connect to the Automatic Storage Management instance as the SYS user with SYSDBA privilege and start the instance if necessary:

    $ $ORACLE_HOME/bin/sqlplus "SYS/SYS_password as SYSDBA"
    SQL> STARTUP
    
    
  4. Enter the following command to view the existing disk groups, their redundancy level, and the amount of free disk space in each one:

    SQL> SELECT NAME,TYPE,TOTAL_MB,FREE_MB FROM V$ASM_DISKGROUP;
    
    
  5. From the output, identify a disk group with the appropriate redundancy level and note the free space that it contains.

  6. If necessary, install or identify the additional disk devices required to meet the storage requirements listed in the previous section.

    Note:

    If you are adding devices to an existing disk group, then Oracle recommends that you use devices that have the same size and performance characteristics as the existing devices in that disk group.

3.6.3 Configuring Database File Storage on ASM and Raw Devices

To configure disks for Automatic Storage Management (ASM) using raw devices, complete the following tasks:

  1. To use ASM with raw partitions, you must create sufficient partitions for your data files, and then bind the partitions to raw devices. To do this, follow the instructions provided for Oracle Clusterware in the section "Configuring Storage for Oracle Clusterware Files on Raw Devices". If you want to configure partitions after installing the database, then refer to Additional Postinstallation Tasks for Tru64.

  2. Make a list of the raw device names you create for the data files, and have the list available during database installation.

When you have completed creating and configuring ASM with raw partitions, proceed to Chapter 4, "Installing Oracle Clusterware".

3.7 Configuring Database File Storage on Raw Devices

The following sections describe how to configure raw partitions for database files.

3.7.1 Identifying Required Raw Partitions for Database Files

Table 3-4 lists the number and size of the raw partitions that you must configure for database files. If you need to create additional raw partitions, then refer to the section Configuring Raw Devices. If you want to configure partitions after installing the database, then refer to Additional Postinstallation Tasks for Tru64.

Table 3-4 Raw Partitions or Logical Volumes Required for Database Files

Number Partition Size (MB) Purpose

1

500

SYSTEM tablespace

1

300 + (Number of instances * 250)

SYSAUX tablespace

Number of instances

500

UNDOTBSn tablespace (One tablespace for each instance)

1

250

TEMP tablespace

1

160

EXAMPLE tablespace

1

120

USERS tablespace

2 * number of instances

120

Two online redo log files for each instance

2

110

First and second control files

1

5

Server parameter file (SPFILE)

1

5

Password file


Note:

If you prefer to use manual undo management, instead of automatic undo management, then, instead of the UNDOTBSn raw devices, you must create a single rollback segment tablespace (RBS) raw device that is at least 500 MB in size.

3.7.2 Creating the Database Configuration Assistant Raw Device Mapping File

Note:

You must complete this procedure only if you are using raw devices for database files. You do not specify the raw devices for the Oracle Clusterware files in the Database Configuration Assistant raw device mapping file.

To allow Database Configuration Assistant to identify the appropriate raw device for each database file, you must create a raw device mapping file, as follows:

  1. Set the ORACLE_BASE environment variable to specify the Oracle base directory that you identified or created previously:

    • Bourne, Bash, or Korn shell:

      $ ORACLE_BASE=/u01/app/oracle ; export ORACLE_BASE
      
      
    • C shell:

      % setenv ORACLE_BASE /u01/app/oracle
      
      
  2. Create a database file subdirectory under the Oracle base directory and set the appropriate owner, group, and permissions on it:

    # mkdir -p $ORACLE_BASE/oradata/dbname
    # chown -R oracle:oinstall $ORACLE_BASE/oradata
    # chmod -R 775 $ORACLE_BASE/oradata
    
    

    In this example, dbname is the name of the database that you chose previously.

  3. Change directory to the $ORACLE_BASE/oradata/dbname directory.

  4. Edit the dbname_raw.conf file in any text editor to create a file similar to the following:

    Note:

    The following example shows a sample mapping file for a two-instance RAC cluster.
    system=dev/rdisk/raw1
    sysaux=dev/rdisk/raw2
    example=dev/rdisk/raw3
    users=dev/rdisk/raw4
    temp=dev/rdisk/raw5
    undotbs1=dev/rdisk/raw6
    undotbs2=dev/rdisk/raw7
    redo1_1=dev/rdisk/raw8
    redo1_2=dev/rdisk/raw9
    redo2_1=dev/rdisk/raw10
    redo2_2=dev/rdisk/raw11
    control1=dev/rdisk/raw12
    control2=dev/rdisk/raw13
    spfile=dev/rdisk/raw14
    pwdfile=dev/rdisk/raw15
    
    

    Use the following guidelines when creating or editing this file:

    • Each line in the file must have the following format:

      database_object_identifier=raw_device_path
      
      
    • For a single-instance database, the file must specify one automatic undo tablespace data file (undotbs1), and at least two redo log files (redo1_1, redo1_2).

    • For a RAC database, the file must specify one automatic undo tablespace data file (undotbsn) and two redo log files (redon_1, redon_2) for each instance.

    • Specify at least two control files (control1, control2).

    • To use manual instead of automatic undo management, specify a single rollback segment tablespace data file (rbs) instead of the automatic undo management tablespace data files.

  5. Save the file, and note the file name that you specified.

  6. If you are using raw devices for database storage, then set the DBCA_RAW_CONFIG environment variable to specify the full path to the raw device mapping file:

    Bourne, Bash, or Korn shell:

    $ DBCA_RAW_CONFIG=$ORACLE_BASE/oradata/dbname/dbname_raw.conf
    $ export DBCA_RAW_CONFIG
    
    

    C shell:

    $ setenv DBCA_RAW_CONFIG=$ORACLE_BASE/oradata/dbname/dbname_raw.conf