5 Configuring Oracle Real Application Clusters Storage

5.1.1 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. It performs striping and mirroring of database files automatically.

  Note:

  For Standard Edition Oracle Database installations using Oracle RAC, ASM is the only supported storage option.

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

  • General Parallel File System (GPFS): Note that if you intend to use GPFS for your data files, then you should create partitions large enough for the database files when you create partitions for Oracle Clusterware. If you intend to store Oracle Clusterware files on GPFS, then you must ensure that GPFS volume sizes are at least 500 MB each.

  • NAS Network File System (NFS) listed on Oracle Certify: Note that if you intend to use NFS for your data files, then you should create partitions large enough for the database files when you create partitions for Oracle Clusterware.

    See Also:

    The Certify page on OracleMetalink for supported Network Attached Storage (NAS) devices, and supported cluster file systems

• Raw Devices: A partition is required for each database file. If you do not use ASM, then for new installations on raw devices, you must use a custom installation.

5.1.2 General Storage Considerations for Oracle RAC

For all installations, you must choose the storage option that you want to use for Oracle Database files, or for Oracle Clusterware with Oracle RAC. If you want to enable automated backups during the 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.

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

The following table shows the storage options supported for storing 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.

https://metalink.oracle.com

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.

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

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

  • All nodes on the cluster have the 11g release 1 (11.1) 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 Oracle RAC database, or an Oracle 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 Oracle RAC database or Oracle RAC database with ASM instance is located.

  • The Oracle RAC database or Oracle 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 Oracle 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 you must configure at least three voting disk areas to provide voting disk redundancy.

5.1.3 After You Have Selected Disk Storage Options

After you have installed and configured Oracle Clusterware storage, and after you have reviewed your disk storage options for Oracle Database files, you must perform the following tasks in the order listed:

1: Check for available shared storage with CVU

Refer to Checking for Available Shared Storage with CVU.

2: Configure storage for Oracle Database files and recovery files

• To use a shared file system for database or recovery file storage, refer to Configuring Storage for Oracle Database Files on a Supported Shared File System, and ensure that in addition to the volumes you create for Oracle Clusterware files, you also create additional volumes with sizes sufficient to store database files.

• To use Automatic Storage Management for database or recovery file storage, refer to "Configuring Disks for Automatic Storage Management"

• To use shared devices for database file storage, refer to "Configuring Storage for Oracle Database Files on Shared Storage Devices".

  Note:

  If you choose to configure database files on raw devices, note that you must complete database software installation first, and then configure storage after installation.

  You cannot use OUI to configure a database that uses raw devices for storage.

5.4.1 Requirements for Using a File System for Oracle Database Files

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

• To use an NFS file system, it must be on a certified NAS device.

• If you choose to place your database 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).

  • The file systems consist of 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.

Use Table 5-2 to determine the partition size for shared file systems.

In Table 5-2, the total required volume size is cumulative. For example, to store all database files on the shared file system, you should have at least 3.4 GB of storage available over a minimum of two volumes.

5.4.2 Deciding to Use NFS for Data Files

Network-attached storage (NAS) systems use NFS to access data. You can store data files on a supported NFS system.

NFS file systems must be mounted and available over NFS mounts before you start installation. Refer to your vendor documentation to complete NFS configuration and mounting.

5.4.3 Deciding to Use Direct NFS for Datafiles

This section contains the following information about Direct NFS:

• About Direct NFS Storage

• Using the Oranfstab File with Direct NFS

• Mounting NFS Storage Devices with Direct NFS

5.4.4 Enabling Direct NFS Client Oracle Disk Manager Control of NFS

Complete the following procedure to enable Direct NFS:

1. Create an oranfstab file with the following attributes for each NFS server to be accessed using Direct NFS:

   • Server: The NFS server name.

   • Path: Up to four network paths to the NFS server, specified either by IP address, or by name, as displayed using the ifconfig command.

   • Export: The exported path from the NFS server.

   • Mount: The local mount point for the NFS server.

   Note:

   On Linux and Unix platforms, the location of the oranfstab file is $ORACLE_HOME/dbs.

   The following is an example of an oranfstab file with two NFS server entries:

   server:  MyDataServer1
   path:  132.34.35.12
   path:  132.34.35.13
   export: /vol/oradata1 mount: /mnt/oradata1
    
   server: MyDataServer2
   path:  NfsPath1
   path:  NfsPath2
   path:  NfsPath3
   path:  NfsPath4
   export: /vol/oradata2 mount: /mnt/oradata2
   export: /vol/oradata3 mount: /mnt/oradata3
   export: /vol/oradata4 mount: /mnt/oradata4
   export: /vol/oradata5 mount: /mnt/oradata5
   

2. Oracle Database uses an ODM library, libnfsodm10.so, to enable Direct NFS. To replace the standard ODM library, $ORACLE_HOME/lib/libodm10.so, with the ODM NFS library, libnfsodm10.so, complete the following steps:

   1. Change directory to $ORACLE_HOME/lib.

   2. Enter the following commands:

      cp libodm10.so libodm10.so_stub
      ln -s libnfsodm10.so libodm10.so
      

5.4.5 Disabling Direct NFS Client Oracle Disk Management Control of NFS

Use one of the following methods to disable the Direct NFS client:

• Remove the oranfstab file.

• Restore the stub libodm10.so file by reversing the process you completed in step 2b, "Enabling Direct NFS Client Oracle Disk Manager Control of NFS"

• Remove the specific NFS server or export paths in the oranfstab file.

5.4.6 Checking NFS Mount Buffer Size Parameters for Oracle RAC

If you are using NFS, then you must set the values for the NFS buffer size parameters rsize and wsize to at least 16384. Oracle recommends that you use the value 32768.

If you are using Direct NFS, then set the rsize and wsize values to 32768. Direct NFS will not serve an NFS server with write size values (wtmax) less than 32768.

For example, if you decide to use rsize and wsize buffer settings with the value 32768, then update the /etc/fstab file on each node with an entry similar to the following:

nfs_server:/vol/DATA/oradata  /home/oracle/netapp     nfs\   
cio,rw,bg,hard,intr,rsize=32768,wsize=32768,tcp,noac,vers=3,timeo=600

5.4.7 Creating Required Directories for Oracle Database Files on Shared File Systems

Use the following instructions to create directories for shared file systems for Oracle Database and recovery files (for example, for a RAC database).

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

   Note:

   The mount point 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 -k command to determine the free disk space on each mounted file system.

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

   File Type	File System Requirements
   Database files	Choose either: A single file system with at least 1.5 GB of free disk space. Two or more file systems with at least 1.5 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 mount point 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 Database, then 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 mount point directories and set the appropriate owner, group, and permissions on them:

   • Database file directory:

     # mkdir /mount_point/oradata
     # chown oracle:oinstall /mount_point/oradata
     # chmod 775 /mount_point/oradata
     

   • Recovery file directory (flash recovery area):

     # mkdir /mount_point/flash_recovery_area
     # chown oracle:oinstall /mount_point/flash_recovery_area
     # chmod 775 /mount_point/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 NFS configuration for Oracle Database shared storage.

5.5.1 Planning Your Shared Storage Device Creation Strategy

Before installing the Oracle Database 11g release 1 (11.1) software with Oracle RAC, create enough partitions of specific sizes to support your database, and also leave a few spare partitions of the same size for future expansion. For example, if you have space on your shared disk array, then select a limited set of standard partition sizes for your entire database. Partition sizes of 50 MB, 100 MB, 500 MB, and 1 GB are suitable for most databases. Also, create a few very small and a few very large spare partitions that are (for example) 1 MB and perhaps 5 GB or greater in size. Based on your plans for using each partition, determine the placement of these spare partitions by combining different sizes on one disk, or by segmenting each disk into same-sized partitions.

5.5.2 Identifying Required Shared Partitions for Database Files

Table 5-3 lists the number and size of the shared partitions that you must configure for database files.

5.6.1 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.

   For Oracle RAC installations, if you choose to enable automated backups and you do not have a shared file system available, 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 non-interactive mode, 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 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 use 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 Oracle 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 Oracle 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, 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. 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.

   For information about completing this task, refer to the "Configuring Database File Storage for Automatic Storage Management and Raw Devices" section.

5.6.2 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.

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 whether an Automatic Storage Management instance is configured on the system:

   $ more /etc/oratab
   

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

   +ASM2:oracle_home_path:N
   

   In this example, +ASM2 is the system identifier (SID) of the Automatic Storage Management instance, with 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, Oracle recommends that you use devices that have the same size and performance characteristics as the existing devices in that disk group.

5.6.3 Configuring Database File Storage for Automatic Storage Management and Raw Devices

To configure disks for use with Automatic Storage Management on AIX, follow these steps:

1. On AIX-based systems, you must apply Program Technical Fix (PTF) U496549 or higher to your system before you use ASM.

2. If necessary, install the shared disks that you intend to use for the Automatic Storage Management disk group and restart the system.

3. To make sure that the disks are available, enter the following command on every node:

   # /usr/sbin/lsdev -Cc disk
   

   The output from this command is similar to the following:

   hdisk0 Available 1A-09-00-8,0  16 Bit LVD SCSI Disk Drive
   hdisk1 Available 1A-09-00-9,0  16 Bit LVD SCSI Disk Drive
   hdisk2 Available 17-08-L       SSA Logical Disk Drive
   

4. If a disk is not listed as available on any node, then enter the following command to configure the new disks:

   # /usr/sbin/cfgmgr
   

5. Enter the following command on any node to identify the device names for the physical disks that you want to use:

   # /usr/sbin/lspv | grep -i none
   

   This command displays information similar to the following for each disk that is not configured in a volume group:

   hdisk2     0000078752249812   None
   

   In this example, hdisk2 is the device name of the disk and 0000078752249812 is the physical volume ID (PVID). The disks that you want to use might have a PVID, but they must not belong to a volume group.

6. Enter commands similar to the following to clear the PVID from each disk device that you want to use:

   # /usr/sbin/chdev -l hdiskn -a pv=clear 
   

   Note:

   If the disk device has a PVID, then ASM will fail to mount the diskgroup created on the disk device.

7. On each of the other nodes, enter a command similar to the following to identify the device name associated with each PVID on that node:

   # /usr/sbin/lspv | grep -i 0000078752249812
   

   The output from this command should be similar to the following:

   hdisk18        0000078752249812        None  
   

   Depending on how each node is configured, the device names may differ between nodes. Note that you will clear PVIDs later in this procedure.

8. If the device names are the same on all nodes, then enter commands similar to the following on all nodes to change the owner, group, and permissions on the character raw device files for the disk devices you want to use with ASM datafiles:

   # chown oracle:dba /dev/rhdiskn
   # chmod 660 /dev/rhdiskn
   

9. If PVIDs are configured, and the device name associated with the PVID for a disk that you want to use is different on any node, then you must create a new device file for the disk on each of the nodes using a common unused name.

   For the new device files, choose an alternative device file name that identifies the purpose of the disk device. Table 5-4 suggests alternative device file names for each file. For database files, replace dbname in the alternative device file name with the name that you chose for the database in step 1.

   Note:

   Alternatively, you can choose a name that contains a number that will never be used on any of the nodes, for example hdisk99.

   To create a new common device file for a disk device on all nodes, follow these steps on each node:

   1. Enter the following command to determine the device major and minor numbers that identify the disk device, where n is the disk number for the disk device on this node:

      # ls -alF /dev/*hdiskn
      

      The output from this command is similar to the following:

      brw------- 1 root system    24,8192 Dec 05 2001  /dev/hdiskn
      crw------- 1 root system    24,8192 Dec 05 2001  /dev/rhdiskn
      

      In this example, the device file /dev/rhdiskn represents the character raw device, 24 is the device major number, and 8192 is the device minor number.

   2. Enter a command similar to the following to create the new device file, specifying the new device file name and the device major and minor numbers that you identified in the previous step:

      Note:

      In the following example, you must specify the character c to create a character raw device file.

      # mknod /dev/ora_ocr_raw_256m c 24 8192
      

   3. Enter commands similar to the following to change the owner, group, and permissions on the character raw device file for the disk:

      • OCR:

        # chown root:oinstall /dev/ora_ocr_raw_256m
        # chmod 640 /dev/ora_ocr_raw_256m
        

      • Voting disk or database files:

        # chown oracle:dba /dev/ora_vote_raw_256m
        # chmod 660 /dev/ora_vote_raw_256m
        

   4. Enter a command similar to the following to verify that you have created the new device file successfully:

      # ls -alF /dev | grep "24,8192"
      

      The output should be similar to the following:

      brw------- 1 root   system   24,8192 Dec 05 2001  /dev/hdiskn
      crw-r----- 1 root   oinstall 24,8192 Dec 05 2001  /dev/ora_ocr_raw_256m
      crw------- 1 root   system   24,8192 Dec 05 2001  /dev/rhdiskn
      

10. To enable simultaneous access to a disk device from multiple nodes, you must set the appropriate Object Data Manager (ODM) attribute listed in the following table to the value shown, depending on the disk type:

    Disk Type	Attribute	Value
    SSA or FAStT disks	reserve_lock	no
    ESS, EMC, HDS, CLARiiON, or MPIO-capable disks	reserve_policy	no_reserve

    
    

    To determine whether the attribute has the correct value, enter a command similar to the following on all cluster nodes for each disk device that you want to use:

    # /usr/sbin/lsattr -E -l hdiskn
    

    If the required attribute is not set to the correct value on any node, enter a command similar to one of the following on that node:

    • SSA and FAStT devices:

      # /usr/sbin/chdev -l hdiskn  -a reserve_lock=no
      

    • ESS, EMC, HDS, CLARiiON, and MPIO-capable devices:

      # /usr/sbin/chdev -l hdiskn  -a reserve_policy=no_reserve
      

11. Enter commands similar to the following on any node to clear the PVID from each disk device that you want to use:

    # /usr/sbin/chdev -l hdiskn -a pv=clear
    

12. Enter commands similar to the following on every node to change the owner, group, and permissions on the character raw device file for each disk that you want to add to the disk group:

    # chown oracle:dba /dev/rhdiskn
    # chmod 660 /dev/rhdiskn
    

    Note:

    If you are using a multi-pathing disk driver with ASM, then ensure that you set the permissions only on the correct logical device name for the disk.

    The device name associated with a disk may be different on other nodes. Ensure that you specify the correct device name on each node.

    When you are installing Oracle Clusterware Services, you must enter the paths to the appropriate device files when prompted for the path of the OCR and voting disk. For example:

    /dev/rhdisk10
    

When you have completed creating and configuring Automatic Storage Management with raw partitions, proceed to Chapter 6, "Installing Oracle Clusterware"

5.7.1 Identifying Required Raw Partitions for Database Files

Table 5-4 lists the number and size of the raw partitions that you must configure for database files.

dbname_system_raw_500m

dbname_sysaux_raw_800m

dbname_undotbsn_raw_500m

dbname_temp_raw_250m

dbname_example_raw_160m

dbname_users_raw_120m

dbname_redon_m_raw_120m

dbname_control{1|2}_raw_110m

dbname_spfile_raw_5m

dbname_pwdfile_raw_5m

5.7.2 Configuring Raw Disk Devices for Database File Storage Without HACMP or GPFS

If you are installing Oracle RAC on an AIX cluster without HACMP or GPFS, you can use shared raw disk devices for database file storage. However, Oracle recommends that you use Automatic Storage Management to store database files in this situation. This section describes how to configure the shared raw disk devices for database files.

To configure shared raw disk devices for Oracle Clusterware files, database files, or both:

1. If you intend to use raw disk devices for database file storage, then specify a name for the database that you want to create.

   The name that you specify must start with a letter and have no more than four characters. For example: orcl.

2. Identify or configure the required disk devices.

   The disk devices must be shared on all of the cluster nodes.

3. As the root user, enter the following command on any node to identify the device names for the disk devices that you want to use:

   # /usr/sbin/lspv | grep -i none 
   

   This command displays information similar to the following for each disk device that is not configured in a volume group:

   hdisk17         0009005fb9c23648                    None  
   

   In this example, hdisk17 is the device name of the disk and 0009005fb9c23648 is the physical volume ID (PVID).

4. If a disk device that you want to use does not have a PVID, then enter a command similar to the following to assign one to it:

   # /usr/sbin/chdev -l hdiskn -a pv=yes
   

5. On each of the other nodes, enter a command similar to the following to identify the device name associated with each PVID on that node:

   # /usr/sbin/lspv | grep -i "0009005fb9c23648"
   

   The output from this command should be similar to the following:

   hdisk18         0009005fb9c23648                    None  
   

   In this example, the device name associated with the disk device (hdisk18) is different on this node.

6. If the device names are the same on all nodes, then enter commands similar to the following on all nodes to change the owner, group, and permissions on the character raw device files for the disk devices you want to use for database files:

   # chown oracle:dba /dev/rhdiskn
   # chmod 660 /dev/rhdiskn
   

7. If the device name associated with the PVID for a disk that you want to use is different on any node, then you must create a new device file for the disk on each of the nodes using a common unused name.

   For the new device files, choose an alternative device file name that identifies the purpose of the disk device. Table 5-3 suggests alternative device file names for each file. For database files, replace dbname in the alternative device file name with the name that you chose for the database in step 1.

   Note:

   Alternatively, you could choose a name that contains a number that will never be used on any of the nodes, for example hdisk99.

   To create a new common device file for a disk device on all nodes, perform these steps on each node:

   1. Enter the following command to determine the device major and minor numbers that identify the disk device, where n is the disk number for the disk device on this node:

      # ls -alF /dev/*hdiskn
      

      The output from this command is similar to the following:

      brw------- 1 root system    24,8192 Dec 05 2001  /dev/hdiskn
      crw------- 1 root system    24,8192 Dec 05 2001  /dev/rhdiskn
      

      In this example, the device file /dev/rhdiskn represents the character raw device, 24 is the device major number, and 8192 is the device minor number.

   2. Enter a command similar to the following to create the new device file, specifying the new device file name (in this example, using an alternative device file name from Table 5-3) and the device major and minor numbers that you identified in the previous step:

      Note:

      As the following example illustrates, you must specify the character c to create a character raw device file.

      # mknod dbname_example_raw_160m c 24 8192
      

   3. Enter a command similar to the following to verify that you have created the new device file successfully:

      # ls -alF /dev | grep "24,8192"
      

      The output should be similar to the following:

      brw------- 1 root   system   24,8192 Dec 05 2001  /dev/hdiskn
      crw-r----- 1 root   oinstall 24,8192 Dec 05 2001  /dev/ora_ocr_raw_256m
      crw------- 1 root   system   24,8192 Dec 05 2001  /dev/rhdiskn
      

8. To enable simultaneous access to a disk device from multiple nodes, you must set the appropriate Object Data Manager (ODM) attribute listed in the following table to the value shown, depending on the disk type:

   Disk Type	Attribute	Value
   SSA, FAStT, or non-MPIO-capable disks	reserve_lock	no
   ESS, EMC, HDS, CLARiiON, or MPIO-capable disks	reserve_policy	no_reserve

   
   

   To determine whether the attribute has the correct value, enter a command similar to the following on all cluster nodes for each disk device that you want to use:

   # /usr/sbin/lsattr -E -l hdiskn
   

   If the required attribute is not set to the correct value on any node, then enter a command similar to one of the following on that node:

   • SSA and FAStT devices

     # /usr/sbin/chdev -l hdiskn  -a reserve_lock=no
     

   • ESS, EMC, HDS, CLARiiON, and MPIO-capable devices

     # /usr/sbin/chdev -l hdiskn  -a reserve_policy=no_reserve
     

9. Enter commands similar to the following on any node to clear the PVID from each disk device that you want to use:

   # /usr/sbin/chdev -l hdiskn -a pv=clear
   

10. If you are using raw disk devices for database files, then follow these steps to create the Database Configuration Assistant raw device mapping file:

    Note:

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

    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. Using any text editor, create a text file similar to the following that identifies the disk device file name associated with each database file.

       Oracle recommends that you use a file name similar to dbname_raw.conf for this file.

       Note:

       The following example shows a sample mapping file for a two-instance Oracle RAC cluster. Some of the devices use alternative disk device file names. Ensure that the device file name that you specify identifies the same disk device on all nodes.

       system=/dev/rhdisk11
       sysaux=/dev/rhdisk12
       example=/dev/rhdisk13
       users=/dev/rhdisk14
       temp=/dev/rhdisk15
       undotbs1=/dev/rhdisk16
       undotbs2=/dev/rhdisk17
       redo1_1=/dev/rhdisk18
       redo1_2=/dev/rhdisk19
       redo2_1=/dev/rhdisk20
       redo2_2=/dev/rhdisk22
       control1=/dev/rhdisk23
       control2=/dev/rhdisk24
       spfile=/dev/dbname_spfile_raw_5m
       pwdfile=/dev/dbname_pwdfile_raw_5m
       

       In this example, dbname is the name of the database.

       Use the following guidelines when creating or editing this file:

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

         database_object_identifier=device_file_name
         

         The alternative device file names suggested in Table 5-4 include the database object identifier that you must use in this mapping file. For example, in the following alternative disk device name, redo1_1 is the database object identifier:

         /dev/rac_redo1_1_raw_120m
         

       • For an Oracle RAC database, the file must specify one automatic undo tablespace datafile (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 RBS tablespace datafile (rbs) instead of the automatic undo management tablespace data files.

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

    6. When you are configuring the oracle user's environment later in this chapter, set the DBCA_RAW_CONFIG environment variable to specify the full path to this file.

11. When you are installing Oracle Clusterware, you must enter the paths to the appropriate device files when prompted for the path of the OCR and Oracle Clusterware voting disk, for example:

    /dev/rhdisk10
    

5.7.3 Configuring Raw Logical Volumes for Database File Storage

This section describes how to configure raw logical volumes for database file storage. The procedures in this section describe how to create a new volume group that contains the logical volumes required for both types of files.

Before you continue, review the following guidelines which contain important information about using volume groups with this release of Oracle RAC:

• You must use concurrent-capable volume groups for database files.

• Oracle Clusterware files require less than 560 MB of disk space, with external redundancy. To make efficient use of the disk space in a volume group, Oracle recommends that you use the same volume group for the logical volumes for both the Oracle Clusterware files and the database files.

• If you are upgrading a database, then you must also create a new logical volume for the SYSAUX tablespace. Refer to the "Configuring Raw Logical Volumes for Database File Storage" section for more information about the requirements for the SYSAUX logical volumes.

  See Also:

  The HACMP documentation for information about removing a volume group from a concurrent resource group.

• You must use a HACMP concurrent resource group to activate new or existing volume groups that contain only database files (not Oracle Clusterware files).

  See Also:

  The HACMP documentation for information about adding a volume group to a new or existing concurrent resource group.

• All volume groups that you intend to use for database files must be activated in concurrent mode before you start the installation.

• The procedures in this section describe how to create basic volumes groups and volumes. If you want to configure more complex volumes (for example, using mirroring), then use this section in conjunction with the HACMP documentation.

5.7.4 Creating a Volume Group for Database Files

To create a volume group for the Oracle Database files:

1. If necessary, install the shared disks that you intend to use.

2. To ensure that the disks are available, enter the following command on every node:

   # /usr/sbin/lsdev -Cc disk
   

   The output from this command is similar to the following:

   hdisk0 Available 1A-09-00-8,0  16 Bit LVD SCSI Disk Drive
   hdisk1 Available 1A-09-00-9,0  16 Bit LVD SCSI Disk Drive
   hdisk2 Available 17-08-L       SSA Logical Disk Drive
   

3. If a disk is not listed as available on any node, then enter the following command to configure the new disks:

   # /usr/sbin/cfgmgr
   

4. Enter the following command on any node to identify the device names and any associated volume group for each disk:

   # /usr/sbin/lspv
   

   The output from this command is similar to the following:

   hdisk0     0000078752249812   rootvg
   hdisk1     none               none
   hdisk4     00034b6fd4ac1d71   ccvg1
   

   For each disk, this command shows:

   • The disk device name

   • Either the 16 character physical volume identifier (PVID) if the disk has one, or none

   • Either the volume group to which the disk belongs, or none

   The disks that you want to use may have a PVID, but they must not belong to existing volume groups.

5. If a disk that you want to use for the volume group does not have a PVID, then enter a command similar to the following to assign one to it:

   # /usr/sbin/chdev -l hdiskn -a pv=yes
   

6. To identify used device major numbers, enter the following command on each node of the cluster:

   # ls -la /dev | more
   

   This command displays information about all configured devices, similar to the following:

   crw-rw----   1 root     system    45,  0 Jul 19 11:56 vg1
   

   In this example, 45 is the major number of the vg1 volume group device.

7. Identify an appropriate major number that is unused on all nodes in the cluster.

8. To create a volume group, enter a command similar to the following, or use SMIT (smit mkvg):

   # /usr/sbin/mkvg -y VGname -B -s PPsize -V majornum -n \
   -C PhysicalVolumes
   

9. The following table describes the options and variables used in this example. Refer to the mkvg man page for more information about these options.

   Command Option	SMIT Field	Sample Value and Description
   -y VGname	VOLUME GROUP name	oracle_vg1 Specify the name for the volume group. The name that you specify could be a generic name, as shown, or it could specify the name of the database that you intend to create.
   -y VGname	VOLUME GROUP name	oracle_vg1 Specify the name for the volume group. The name that you specify could be a generic name, as shown, or for a database volume group, it could specify the name of the database that you intend to create.
   -B	Create a big VG format Volume Group	Specify this option to create a big VG format volume group. Note: If you are using SMIT, then choose yes for this field.
   -s PPsize	Physical partition SIZE in megabytes	32 Specify the size of the physical partitions for the database. The sample value shown enables you to include a disk up to 32 GB in size (32 MB * 1016).
   -V Majornum	Volume Group MAJOR NUMBER	46 Specify the device major number for the volume group that you identified in Step 7.
   -n	Activate volume group AUTOMATICALLY at system restart	Specify this option to prevent the volume group from being activated at system restart. Note: If you are using SMIT, then choose no for this field.
   -C	Create VG Concurrent Capable	Specify this option to create a concurrent capable volume group. Note: If you are using SMIT, then choose yes for this field.
   PhysicalVolumes	PHYSICAL VOLUME names	hdisk3 hdisk4 Specify the device names of the disks that you want to add to the volume group.

   
   

10. Enter a command similar to the following to vary on the volume group that you created:

    # /usr/sbin/varyonvg VGname
    

5.7.5 Creating Database File Raw Logical Volumes in the New Volume Group

To create the required raw logical volumes in the new volume group:

1. Choose a name for the database that you want to create.

   The name that you choose must start with a letter and have no more than four characters, for example, orcl.

2. Identify the logical volumes that you must create.

   Table 5-5 lists the number and size of the logical volumes that you must create for database files.

   Table 5-5 Raw Logical Volumes Required for Database Files

   Number	Size (MB)	Purpose and Sample Logical Volume Name
   1	500	SYSTEM tablespace: dbname_system_raw_500m
   1	500	SYSAUX tablespace: dbname_sysaux_raw_500m
   1	300 + (Number of instances * 250)	SYSAUX tablespace: dbname_sysaux_raw_800m
   1	500	UNDOTBS1 tablespace: dbname_undotbs1_raw_500m
   Number of instances	500	UNDOTBSn tablespace (One tablespace for each instance, where n is the number of the instance): dbname_undotbsn_raw_500m
   1	250	TEMP tablespace: dbname_temp_raw_250m
   1	160	EXAMPLE tablespace: dbname_example_raw_160m
   1	120	USERS tablespace: dbname_users_raw_120m
   2	120	Two online redo log files (where m is the log number, 1 or 2): dbname_redo1_m_raw_120m
   2 * number of instances	120	Two online redo log files for each instance (where n is the number of the instance and m is the log number, 1 or 2): dbname_redon_m_raw_120m
   2	110	First and second control files: dbname_control{1|2}_raw_110m
   1	5	Server parameter file (SPFILE): dbname_spfile_raw_5m
   1	5	Password file: dbname_pwdfile_raw_5m

   
   

3. To create each required logical volume for data files, Oracle recommends that you use a command similar to the following to create logical volumes with a zero offset:

   # /usr/sbin/mklv -y LVname -T O -w n -s n -r n VGname NumPPs
   

   In this example:

   • LVname is the name of the logical volume that you want to create

   • The -T O option specifies that the device subtype should be z, which causes Oracle to use a zero offset when accessing this raw logical volume

   • VGname is the name of the volume group where you want to create the logical volume

   • NumPPs is the number of physical partitions to use

     To determine the value to use for NumPPs, divide the required size of the logical volume by the size of the physical partition and round the value up to an integer. For example, if the size of the physical partition is 32 MB and you want to create a 500 MB logical volume, then you should specify 16 for the NumPPs (500/32 = 15.625).

   Using a zero offset improves database performance and fixes the issues described in Oracle bug 2620053.

   Note:

   On raw logical volumes, if you create tablespaces in datafiles that are not created in this way, a message is recorded in the alert.log file.

   If you prefer, you can also use the command smit mklv to create raw logical volumes.

   The following example shows the command used to create a logical volume for the SYSAUX tablespace of the test database in the oracle_vg1 volume group with a physical partition size of 32 MB (800/32 = 25):

   # /usr/sbin/mklv -y test_sysaux_raw_800m -T O -w n -s n -r n oracle_vg1 25
   

4. Change the owner, group, and permissions on the character device files associated with the logical volumes that you created, as follows:

   Note:

   The device file associated with the Oracle Cluster Registry must be owned by root. All other device files must be owned by the Oracle software owner user (oracle).

   # chown oracle:dba /dev/rdbname*
   # chmod 660 /dev/rdbname*
   

5.7.6 Importing the Database File Volume Group on the Other Cluster Nodes

To make the database file volume group available to all nodes in the cluster, you must import it on each node, as follows:

1. Because the physical volume names may be different on the other nodes, enter the following command to determine the PVID of the physical volumes used by the volume group:

   # /usr/sbin/lspv
   

2. Note the PVIDs of the physical devices used by the volume group.

3. To vary off the volume group that you want to use, enter a command similar to the following on the node where you created it:

   # /usr/sbin/varyoffvg VGname
   

4. On each cluster node, complete the following steps:

   1. Enter the following command to determine the physical volume names associated with the PVIDs you noted previously:

      # /usr/sbin/lspv
      

   2. On each node of the cluster, enter commands similar to the following to import the volume group definitions:

      # /usr/sbin/importvg -y VGname -V MajorNumber PhysicalVolume
      

      In this example, MajorNumber is the device major number for the volume group and PhysicalVolume is the name of one of the physical volumes in the volume group.

      For example, to import the definition of the oracle_vg1 volume group with device major number 45 on the hdisk3 and hdisk4 physical volumes, enter the following command:

      # /usr/sbin/importvg -y oracle_vg1 -V 45 hdisk3
      

   3. Change the owner, group, and permissions on the character device files associated with the logical volumes you created, as follows:

      # chown oracle:dba /dev/rdbname*
      # chmod 660 /dev/rdbname*
      

   4. Enter the following command to ensure that the volume group will not be activated by the operating system when the node starts:

      # /usr/sbin/chvg -a n VGname
      

5.7.7 Activating the Database File Volume Group in Concurrent Mode on All Cluster Nodes

To activate the volume group in concurrent mode on all cluster nodes, enter the following command on each node:

# /usr/sbin/varyonvg -c VGname

5.7.8 Creating the Database Configuration Assistant Raw Device Mapping File

To enable 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. Enter the following command to create a text file that you can use to create the raw device mapping file:

   # find /dev -user oracle -name 'r*' -print > dbname_raw.conf
   

5. 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 Oracle RAC cluster.

   system=/dev/rdbname_system_raw_500m
   sysaux=/dev/rdbname_sysaux_raw_800m
   example=/dev/rdbname_example_raw_160m
   users=/dev/rdbname_users_raw_120m
   temp=/dev/rdbname_temp_raw_250m
   undotbs1=/dev/rdbname_undotbs1_raw_500m
   undotbs2=/dev/rdbname_undotbs2_raw_500m
   redo1_1=/dev/rdbname_redo1_1_raw_120m
   redo1_2=/dev/rdbname_redo1_2_raw_120m
   redo2_1=/dev/rdbname_redo2_1_raw_120m
   redo2_2=/dev/rdbname_redo2_2_raw_120m
   control1=/dev/rdbname_control1_raw_110m
   control2=/dev/rdbname_control2_raw_110m
   spfile=/dev/rdbname_spfile_raw_5m
   pwdfile=/dev/rdbname_pwdfile_raw_5m
   

   In this example, dbname is the name of the database.

   Use the following guidelines when creating or editing this file:

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

     database_object_identifier=logical_volume
     

     The logical volume names suggested in this manual include the database object identifier that you must use in this mapping file. For example, in the following logical volume name, redo1_1 is the database object identifier:

     /dev/rrac_redo1_1_raw_120m
     

   • The file must specify one automatic undo tablespace datafile (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 RBS tablespace datafile (rbs) instead of the automatic undo management tablespace data files.

6. Save the file and note the file name that you specified.

7. When you are configuring the oracle user's environment later in this chapter, set the DBCA_RAW_CONFIG environment variable to specify the full path to this file.