2 Oracle Database Preinstallation Requirements

2.2.1 Memory Requirements

The following are the memory requirements for installing Oracle Database 11g release 1:

• At least 1 GB of physical RAM

  To determine the physical RAM size, enter the following command:

  # grep MemTotal /proc/meminfo
  
  

  If the size of the physical RAM is less than the required size, then you must install more memory before continuing.

• The following table describes the relationship between installed RAM and the configured swap space requirement:

  RAM	Swap Space
  Between 257 MB and 512 MB	Double the size of RAM
  Between 513 MB and 2048 MB	1.5 times the size of RAM
  Between 2049 MB and 8192 MB	Equal to the size of RAM
  More than 8192 MB	0.75 times the size of RAM

  
  

  To determine the size of the configured swap space, enter the following command:

  # grep SwapTotal /proc/meminfo
  
  

  If necessary, refer to the operating system documentation for information about how to configure additional swap space.

To determine the available RAM and swap space, enter the following command:

# free

Automatic Memory Management

Starting with Oracle Database 11g, the Automatic Memory Management feature requires more shared memory (/dev/shm)and file descriptors. The shared memory should be sized to be at least the greater of MEMORY_MAX_TARGET and MEMORY_TARGET for each Oracle instance on the computer. If MEMORY_MAX_TARGET or MEMORY_TARGET is set to a non zero value, and the shared memory is not sized correctly, you will notice ORA-00845 error at startup. The number of file descriptors for each Oracle instance should be at least 512*PROCESSES. Also, the limit of descriptors for each process should be at least 512. If file descriptors are not sized correctly, you will notice ORA-27123 from various Oracle processes and potentially Linux Error EMFILE (Too many open files) errors in non-Oracle processes.

To determine the amount of shared memory available, enter the following command:

# df -k /dev/shm/

On the Initialization Parameters page, if you are installing on a Linux system, note that Memory Size (SGA and PGA), which sets the initialization parameter MEMORY_TARGET or MEMORY_MAX_TARGET, cannot be greater than the shared memory file system on the operating system.

For example, if the shared memory file system allocation on your system is 1 GB, but you set Memory Size (MEMORY_TARGET) to 2 GB, then you receive the following error during database startup:

ORA-00845: MEMORY_TARGET not supported on this system
ORA-01078: Failure in processing system parameters

In addition, if you click All Initialization Parameters, note that if your global database name is longer than 8 characters, then the database name value (in the DB_NAME parameter) is truncated to the first eight characters, and the DB_UNIQUE_NAME parameter value is set to the global name.

2.2.2 Disk Space Requirements

The following are the disk space requirements for installing Oracle Database 11g release 1:

• Between 150 and 200 MB of disk space in the /tmp directory

  To determine the amount of disk space available in the /tmp directory, enter the following command:

  # df -k /tmp
  
  

  If there is less than 400 MB of free disk space available in the /tmp directory, then complete one of the following steps:

  • Delete unnecessary files from the /tmp directory to meet the disk space requirement.

  • Set the TMP and TMPDIR environment variables when setting the oracle user's environment (described later).

  • Extend the file system that contains the /tmp directory. If necessary, contact the system administrator for information about extending file systems.

• Between 1.5 GB and 3.5 GB of disk space for the Oracle software, depending on the installation type

  To determine the amount of free disk space on the system, enter the following command:

  # df -k
  

  Installation Type	Requirement for Software Files (GB)
  Enterprise Edition	3.47
  Standard Edition	3.22
  Custom (maximum)	3.45

  
  

• Enterprise Edition and Standard Edition require 1.6 GB of disk space for datafiles. However, Custom DB requires 1.81 GB.

  Note:

  The disk space requirement for databases that use Automatic Storage Management is described later in this chapter.

  Additional disk space, either on a file system or in an Automatic Storage Management disk group, is required for the flash recovery area if you choose to configure automated backups.

2.2.3 Recommended Hardware Requirement for SQL Developer

The following are the recommended CPU, Memory and Display requirements for SQL Developer.

2.3.1 Operating System Requirements

The following are the operating stem requirements for Oracle Database 11g release 1:

• Asianux 2.0

• Asianux 3.0

• Oracle Enterprise Linux 4.0

• Oracle Enterprise Linux 5.0

• Red Hat Enterprise Linux 4.0

• Red Hat Enterprise Linux 5.0

• SUSE Enterprise Linux 10.0

To determine the distribution and version of Linux installed, enter the following command:

# cat /proc/version

2.3.2 Kernel Requirements

The following are the Kernel requirements for Oracle Database 11g release 1:

• For Asianux 2, Oracle Enterprise Linux 4.0, and Red Hat Enterprise Linux 4.0:

  2.6.9

• For Asianux 3, Oracle Enterprise Linux 5.0, and Red Hat Enterprise Linux 5.0:

  2.6.18

• For SUSE 10:

  2.6.16.21

To determine whether the required kernel is installed, enter the following command:

# uname -r

The following is a sample output displayed by running this command on a Red Hat Enterprise Linux 4.0 system:

2.6.9-55.0.0.0.2.EL

In this example, the output shows the kernel version (2.6.9) and errata level (55.0.0.0.2.EL) on the system.

If the kernel version does not meet the requirement specified earlier in this section, then contact the operating system vendor for information about obtaining and installing kernel updates.

2.3.3 Package Requirements

The following are the list of packages required for Oracle Database 11g release 1.

binutils-2.15.92.0.2-18
compat-libstdc++-33.2.3-47.3
elfutils-libelf-0.97-5
elfutils-libelf-devel-0.97-5
glibc-2.3.9.4-2.19
glibc-common-2.3.9.4-2.19
glibc-devel-2.3.9.4-2.19
gcc-3.4.5-2
gcc-c++-3.4.5-2
libaio-devel-0.3.105-2
libaio-0.3.105-2
libgcc-3.4.5
libstdc++-3.4.5-2
libstdc++-devel-3.4.5-2
make-3.80-5
sysstat-5.0.5
unixODBC-2.2.11
unixODBC-devel-2.2.11

binutils-2.17.50.0.6-2.el5
compat-libstdc++-33-3.2.3-61
elfutils-libelf-0.125-3.el5
elfutils-libelf-devel-0.125
glibc-2.5-12
glibc-common-2.5-12
glibc-devel-2.5-12
gcc-4.1.1-52
gcc-c++-4.1.1-52
libaio-0.3.106
libaio-devel-0.3.106 
libgcc-4.1.1-52
libstdc++-4.1.1 
libstdc++-devel-4.1.1-52.e15
make-3.81-1.1
sysstat-7.0.0
unixODBC-2.2.11
unixODBC-devel-2.2.11

binutils-2.16.91.0.5
compat-libstdc++-5.0.7
glibc-2.4-31.2
glibc-devel-2.4-31.2
gcc-4.1.0
ksh-93r-12.9
libaio-0.3.104
libaio-devel-0.3.104
libelf-0.8.5
libgcc-4.1.0
libstdc++-4.1.0
libstdc++-devel-4.1.0
make-3.80
sysstat-6.0.2
unixODBC-2.2.11
unixODBC-devel-2.2.11

To determine whether the required packages are installed, enter commands similar to the following:

# rpm -q package_name

If a package is not installed, then install it from the Linux distribution media or download the required package version from the Linux vendor's Web site.

2.3.4 Compiler Requirements

The following are the compiler requirements for Pro*C/C++, Oracle Call Interface, Oracle C++ Call Interface, and Oracle XML Developer's Kit (XDK) with Oracle Database 11g release 1:

Intel C++ Compiler 9.1 or later and the version of GNU C and C++ compilers listed under "Package Requirements" are supported with these products.

2.3.5 Additional Software Requirements

Depending on the components you want to use, you must ensure that the following software are installed:

• Oracle ODBC Drivers

• Integrated Development Environment

• Oracle Messaging Gateway

• Browser Requirements

• Oracle XML DB for Oracle Application Express

• PL/SQL Web Toolkit

• Oracle Text

2.5.1 Configuring Name Resolution

When you run Oracle Universal Installer, an error may occur if name resolution is not set up. To avoid this error, before you begin installation, you must ensure that host names are resolved through the /etc/hosts file.

To ensure that host names are resolved only through the /etc/hosts file:

1. Verify that the /etc/hosts file is used for name resolution. You can do this by checking the hosts file entry in the nsswitch.conf file as follows:

   # cat /etc/nsswitch.conf | grep hosts
   
   

   The output of this command should contain an entry for files.

2. Verify that the host name has been set by using the hostname command as follows:

   # hostname
   
   

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

   myhost.mycomputer.com
   
   

3. Verify that the domain name has not been set dynamically by using the domainname command as follows:

   # domainname
   
   

   This command should not return any results.

4. Verify that the hosts file contains the fully qualified host name by using the following command:

   # cat /etc/hosts 
   
   

   The output of this command should contain an entry for the fully qualified host name and localhost.

   For example:

   127.0.0.1    localhost.localdomain localhost 
   192.168.100.16  myhost.us.mycompany.com myhost 
   
   

   If the hosts file does not contain the fully qualified host name, then open the file and make the required changes in it.

2.5.2 Installing on DHCP Computers

Dynamic Host Configuration Protocol (DHCP) assigns dynamic IP addresses on a network. Dynamic addressing enables a computer to have a different IP address each time it connects to the network. In some cases, the IP address can change while the computer is still connected. You can have a mixture of static and dynamic IP addressing in a DHCP system.

In a DHCP setup, the software tracks IP addresses, which simplifies network administration. This lets you add a new computer to the network without having to manually assign that computer a unique IP address.

2.5.3 Installing on Multihomed Computers

You can install Oracle Database on a multihomed computer. A multihomed computer is associated with multiple IP addresses. This is typically achieved by having multiple network cards on the computer. Each IP address is associated with a host name. In addition, you can set up aliases for the host name. By default, Oracle Universal Installer uses the ORACLE_HOSTNAME environment variable setting to find the host name. If ORACLE_HOSTNAME is not set and you are installing on a computer that has multiple network cards, then Oracle Universal Installer determines the host name by using the first entry in the /etc/hosts file.

Clients must be able to access the computer either by using this host name or by using aliases for this host name. To verify this, ping the host name from the client computers using the short name (hostname only) and the full name (hostname and domain name). Both tests must be successful.

Setting the ORACLE_HOSTNAME Environment Variable

Use the following procedure to set the ORACLE_HOSTNAME environment variable.

For example, if the fully qualified host name is somehost.us.example.com, then enter one of the following commands:

Bourne, Bash, or Korn shell:

$ ORACLE_HOSTNAME=somehost.us.example.com
$ export ORACLE_HOSTNAME

C shell:

% setenv ORACLE_HOSTNAME somehost.us.example.com

2.5.4 Installing on Computers with Multiple Aliases

A computer with multiple aliases is registered with the naming service under a single IP but with multiple aliases. The naming service resolves any of those aliases to the same computer. Before installing Oracle Database on such a computer, set the ORACLE_HOSTNAME environment variable to the computer whose host name you want to use.

2.5.5 Installing on Non-Networked Computers

You can install Oracle Database on a non-networked computer. If the computer, such as a laptop, is configured for DHCP and you plan to connect the computer to the network after the Oracle Database installation, then use the ping command on the computer on which you want to install the database to check if the computer can connect to itself. Perform this step by first using only the host name and then using the fully qualified name, which should be in the /etc/hosts file.

If the ping command fails, then contact the network administrator.

Connecting the Computer to the Network after Installation

If you connect the computer to a network after installation, then the Oracle Database instance on the computer can work with other instances on the network. The computer can use a static IP or DHCP, depending on the network to which you are connected.

2.6.1 Creating the Oracle Inventory Group

Log in as root, and use the following instructions to locate or create the Oracle Inventory group and a software owner:

• Determining Whether the Oracle Inventory Group Exists

• Creating the Oracle Inventory Group

Determining Whether the Oracle Inventory Group Exists

When you install Oracle software on the system for the first time, Oracle Universal Installer creates the oraInst.loc file. This file identifies the name of the Oracle Inventory group (typically, oinstall), and the path of the Oracle Inventory directory. An oraInst.loc file has contents similar to the following:

inventory_loc=central_inventory_location
inst_group=group

In the preceding example, central_inventory_location is the location of the Oracle Central Inventory, and group is the name of the group that has permissions to write to the central inventory.

If you have an existing Oracle Inventory, then ensure that you use the same Oracle Inventory for all Oracle software installations, and ensure that all Oracle software users you intend to use for installation have permissions to write to this directory.

To determine whether the Oracle Inventory group exists, enter the following command:

# more /etc/oraInst.loc

If the oraInst.loc file exists, then the output from this command is similar to the following:

inventory_loc=/u01/app/oraInventory
inst_group=oinstall

In the previous output example:

• The inventory_loc group shows the location of the Oracle Inventory

• The inst_group parameter shows the name of the Oracle Inventory group (in this example, oinstall).

Creating the Oracle Inventory Group

If the oraInst.loc file does not exist, then create the Oracle Inventory group by entering the following command:

# /usr/sbin/groupadd oinstall

2.6.2 Creating the OSDBA Group

You must create an OSDBA group in the following circumstances:

• An OSDBA group does not exist, for example, if this is the first installation of Oracle Database software on the system

• An OSDBA group exists, but you want to give a different group of operating system users database administrative privileges in a new Oracle installation

To determine whether the OSDBA group exists, enter the following command:

# grep OSDBA_group_name /etc/group

If the OSDBA group does not exist or if you require a new OSDBA group, then create it as follows. In the following command, use the group name dba unless a group with that name already exists.

# /usr/sbin/groupadd dba

2.6.3 Creating an OSOPER Group (Optional)

Create an OSOPER group only if you want to identify a group of operating system users with a limited set of database administrative privileges (SYSOPER operator privileges). For most installations, it is sufficient to create only the OSDBA group. If you want to use an OSOPER group, then you must create it in the following circumstances:

• If an OSOPER group does not exist, for example, if this is the first installation of Oracle Database software on the system

• If an OSOPER group exists, but you want to give a different group of operating system users database operator privileges in a new Oracle installation

If you require a new OSOPER group, then create it as follows. In the following command, use the group name oper unless a group with that name already exists.

# /usr/sbin/groupadd oper

2.6.4 Creating an OSASM Group

Create an OSASM group only if you want SYSASM as a system privilege that enables the separation of the SYSDBA database administration privilege from the ASM storage administration privilege. If you want to use an OSASM group, then you must create it in the following circumstances:

• If an OSASM group does not exist, for example, if this is the first installation of Oracle Database software on the system

• If an OSASM group exists, but you want to give a different group of operating system users database operator privileges in a new Oracle installation

To determine whether the OSASM group exists, enter the following command:

# grep OSASM_group_name /etc/group

If the OSASM group does not exist or if you require a new OSASM group, then create it as follows. In the following command, use the group name asadmin unless a group with that name already exists.

# /usr/sbin/groupadd asadmin

2.6.5 Creating the Oracle Software Owner User

You must create an Oracle software owner user in the following circumstances:

• If an Oracle software owner user does not exist, for example, if this is the first installation of Oracle software on the system

• If an Oracle software owner user exists, but you want to use a different operating system user, with different group membership, to give database administrative privileges to those groups in a new Oracle Database installation

# id oracle

uid=440(oracle) gid=200(oinstall) groups=201(dba),202(oper)

# /usr/sbin/usermod -g oinstall -G dba[,oper] oracle

2.6.6 Verifying that the User nobody Exists

Before installing the software, perform the following procedure to verify that the nobody user exists on the system:

1. To determine whether the user exists, enter the following command:

   # id nobody
   
   

   If this command displays information about the nobody user, then you do not have to create that user.

2. If the nobody user does not exist, then enter the following command to create it:

   # /usr/sbin/useradd -g nobody
   

2.8.1 Oracle Base Directory

The Oracle base directory is a top-level directory for Oracle software installations. On Linux systems, the Optimal Flexible Architecture (OFA) guidelines recommend that you use a path similar to the following for the Oracle base directory:

/mount_point/app/oracle_sw_owner

In this example:

• mount_point is the mount point directory for the file system that will contain the Oracle software.

  The examples in this guide use /u01 for the mount point directory. However, you could choose another mount point directory, such as /oracle or /opt/oracle.

• oracle_sw_owner is the operating system user name of the Oracle software owner, for example oracle.

You need to specify the ORACLE_BASE folder that contains all Oracle products.

You can use the same Oracle base directory for more than one installation or you can create separate Oracle base directories for different installations. If different operating system users install Oracle software on the same system, then each user must create a separate Oracle base directory. The following example Oracle base directories could all exist on the same system:

/u01/app/oracle
/u01/app/orauser
/opt/oracle/app/oracle

2.8.2 Oracle Inventory Directory

The Oracle Inventory directory (oraInventory) stores an inventory of all software installed on the system. It is required by, and shared by, all Oracle software installations on a single system. If you have an existing Oracle Inventory path, then Oracle Universal Installer continues to use that Oracle Inventory.

The first time you install Oracle software on a system, Oracle Universal Installer checks to see if you have created an OFA-compliant path in the format u[01-09]/app, such as /u01/app, and that the user running the installation has permissions to write to that path. If this is true, then Oracle Universal Installer creates the Oracle Inventory directory in the path /u[01-09]/app/oraInventory. For example:

/u01/app/oraInventory

If you have set the environment variable $ORACLE_BASE for the oracle user, then Oracle Universal Installer creates the Oracle Inventory directory in the path $ORACLE_BASE/../oraInventory. For example, if $ORACLE_BASE is set to /opt/oracle/11, then the Oracle Inventory directory is created in the path /opt/oracle/oraInventory.

If you have created neither an OFA-compliant path nor set $ORACLE_BASE, then the Oracle Inventory directory is placed in the home directory of the user that is performing the installation. For example:

/home/oracle/oraInventory

Oracle Universal Installer creates the directory that you specify and sets the correct owner, group, and permissions for it. You do not need to create it.

2.8.3 Oracle Home Directory

The Oracle home directory is the directory where you choose to install the software for a particular Oracle product. You must install different Oracle products, or different releases of the same Oracle product, in separate Oracle home directories. When you run Oracle Universal Installer, it prompts you to specify the path to this directory, as well as a name that identifies it. The directory that you specify must be a subdirectory of the Oracle base directory. Oracle recommends that you specify a path similar to the following for the Oracle home directory:

oracle_base/product/11.1.0/db_1

Oracle Universal Installer creates the directory path that you specify under the Oracle base directory. It also sets the correct owner, group, and permissions on it. You do not need to create this directory.

2.9.1 Identifying an Existing Oracle Base Directory

Existing Oracle base directories may not have paths that comply with OFA guidelines. However, if you identify an existing Oracle Inventory directory or existing Oracle home directories, then you can usually identify the Oracle base directories, as follows:

• Identifying an existing Oracle Inventory directory

  Enter the following command to view the contents of the oraInst.loc file:

  # more /etc/oraInst.loc
  
  

  If the oraInst.loc file exists, then the output from this command is similar to the following:

  inventory_loc=/u01/app/oraInventory
  inst_group=oinstall
  
  

  The inventory_loc parameter identifies the Oracle Inventory directory (oraInventory). The parent directory of the oraInventory directory is typically an Oracle base directory. In the previous example, /u01/app/oracle is an Oracle base directory.

  Note:

  Oracle recommends that you do not put the oraInventory directory under Oracle base for a new installation. However, if you have an existing installation, then you should follow the steps suggested in this section.

• Identifying an existing Oracle home directory

  Enter the following command to view the contents of the oratab file:

  # more /etc/oratab
  
  

  If the oratab file exists, then it contains lines similar to the following:

  *:/u03/app/oracle/product/11.1.0/db_1:N
  *:/opt/orauser/infra_904:N
  *:/oracle/9.2.0:N
  
  

  The directory paths specified on each line identify Oracle home directories. Directory paths that end with the user name of the Oracle software owner that you want to use are valid choices for an Oracle base directory. If you intend to use the oracle user to install the software, then you could choose one of the following directories from the previous example:

  /u03/app/oracle
  /oracle
  

  Note:

  If possible, choose a directory path similar to the first (/u03/app/oracle). This path complies with the OFA guidelines.

• Identifying an existing Oracle base directory

  After you have located the Oracle home directory, you can issue the following command to confirm the location of Oracle base:

  cat inventory/ContentsXML/oraclehomeproperties.xml
  
  

Before deciding to use an existing Oracle base directory for this installation, ensure that it satisfies the following conditions:

• It should not be on the same file system as the operating system.

• It must have sufficient free disk space, as follows:

  Requirement	Free Disk Space
  The Oracle base directory will contain only software files.	Up to 3 GB
  The Oracle base directory will contain both software and database files (not recommended for production databases).	Up to 5.4 GB

  
  

  To determine the free disk space on the file system where the Oracle base directory is located, enter the following command:

  # df -k oracle_base_path
  
  

To continue:

• If an Oracle base directory exists and you want to use it, then refer to the "Choosing a Storage Option for Oracle Database and Recovery Files" section.

  When you configure the oracle user's environment later in this chapter, set the ORACLE_BASE environment variable to specify the directory you chose.

• If an Oracle base directory does not exist on the system or if you want to create an Oracle base directory, then refer to the following section.

2.9.2 Creating an Oracle Base Directory

Before you create an Oracle base directory, you must identify an appropriate file system with sufficient free disk space, as follows:

To identify an appropriate file system:

1. To determine the free disk space on each mounted file system use the following command:

   # df -k 
   
   

2. From the display, identify a file system that has appropriate free space.

   The file system that you identify can be a local file system, a cluster file system, or an NFS file system on a certified NAS device.

3. Note the name of the mount point directory for the file system that you identified.

To create the Oracle base directory and specify the correct owner, group, and permissions for it:

1. Enter commands similar to the following to create the recommended subdirectories in the mount point directory that you identified and set the appropriate owner, group, and permissions on them:

   # mkdir -p /mount_point/app
   # chown -R oracle:oinstall /mount_point/app
   # chmod -R 775 /mount_point/app/
   
   

   For example:

   # mkdir -p /u01/app
   # chown -R oracle:oinstall /u01/app
   # chmod -R 775 /u01/app/
   
   

2. When you configure the oracle user's environment later in this chapter, set the ORACLE_BASE environment variable to specify the Oracle base directory that you have created.

2.11.1 Guidelines for Placing Oracle Database Files on a File System

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

• The default path suggested by Oracle Universal Installer for the database file directory is a subdirectory of the Oracle base directory.

• 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, then 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, then 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 described in Appendix D, "Optimal Flexible Architecture". 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, then the file system (or file systems) that you choose must have at least 1.5 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.

2.11.2 Creating Required Directories

To create directories for the Oracle database, or recovery files on separate file systems to the Oracle base directory:

1. To determine the free disk space on each mounted file system use the following command:

   # df -k 
   
   

2. 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 2.4 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.

3. Note the names of the mount point directories for the file systems that you identified.

4. Enter 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
     
     

     The default location for Database file directory is $ORACLE_BASE/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
     
     

     The default flash recovery area is $ORACLE_BASE/flash_recovery_area. However, Oracle recommends that you keep the flash recovery area on a separate physical disk than that of the database file directory. This will enable you use the flash recovery area to retrieve data if the disk containing oradata is unusable due to any reasons.

5. If you also want to use Automatic Storage Management for storage, then refer to the following section:

   "Preparing Disk Groups for an Automatic Storage Management Installation"

   Otherwise, refer to the "Stopping Existing Oracle Processes" section.

2.12.1 General Steps for Configuring Automatic Storage Management

The following are the general steps to configure Automatic Storage Management:

1. Identify the storage requirements of the site.

2. Optionally, use an existing Automatic Storage Management disk group.

3. If you are creating a new Automatic Storage Management disk group, create partitions for DAS or SAN disks.

4. Use one of the following methods to complete the Automatic Storage Management configuration:

   • If you plan to install Oracle Database using interactive mode, Oracle Universal Installer prompts you for the Automatic Storage Management disk configuration information during the installation.

   • If you plan to install Oracle Database using noninteractive mode, you will need to manually configure the disks before performing the installation.

2.12.2 Step 1: Identifying Storage Requirements for Automatic Storage Management

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

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 data files and recovery files. You can use the file system for one file type and Automatic Storage Management for the other. If you plan to use Automatic Storage Management for both data files and recovery files, then you should create separate Automatic Storage Management disk groups for the data files and the recovery files.

   If you plan to enable automated backups during the installation, then 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 Oracle Database Configuration Assistant in interactive mode, by choosing the Advanced database configuration option for example, then you can decide whether you want to use the same Automatic Storage Management disk group for database files and recovery files, or you can choose to use different disk groups for each file type. Ideally, you should create separate Automatic Storage Management disk groups for data files and for recovery files.

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

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

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

   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.

     If you select this option, Automatic Storage Management does not mirror the contents of the disk group. Choose this redundancy level under any one of the following conditions:

     • When the disk group contains devices, such as RAID devices, that provide their own data protection

     • The use of the database does not require uninterrupted access to data, for example, in a development environment where you have a suitable backup strategy

   • Normal redundancy

     In a normal redundancy disk group, by default Automatic Storage Management uses two-way mirroring for datafiles and three-way mirroring for control files, to increase performance and reliability. Alternatively, you can use two-way mirroring or no mirroring. A normal redundancy disk group requires a minimum of two failure groups (or two disk devices) if you are using two-way mirroring. 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

     The contents of the disk group are three-way mirrored by default. To create a disk group with high redundancy, you must specify at least three failure groups (a minimum of 3 devices).

     Although high-redundancy disk groups provide a high level of data protection, you must consider the higher cost of additional storage devices before deciding to use this redundancy level.

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 the installation:

   Redundancy Level	Minimum Number of Disks	Data 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

   
   

   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 step 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 perform this step only if you intend to use an installation method that runs Oracle 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 the database against hardware failure by associating a set of disk devices in a custom failure group. By default, each device comprises its 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 avoid failures of this type, you can 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. Apply the following guidelines when identifying appropriate disk devices:

   • All 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 its use. Logical volume managers can hide the physical disk architecture. This would prevent Automatic Storage Management from optimizing I/O across the physical devices.

   See Also:

   "Step 4: Configuring Disks for Automatic Storage Management" for information about completing this task

2.12.3 Step 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 Oracle Database Configuration Assistant in interactive mode (for example, choosing the Advanced database configuration option), then you can decide whether you want to create a disk group or use an existing one.

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

• If you select an installation method that runs Oracle 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 whether an existing Automatic Storage Management disk group exists, or to determine whether 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, then the oratab file should contain a line similar to the following:

   +ASM:oracle_home_path:N
   
   

   In this example, +ASM is the system identifier (SID) of the Automatic Storage Management instance 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. Open a shell prompt and temporarily 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.

   For example, if the Automatic Storage Management SID is named OraDB11g+ASM and is located in the asm subdirectory of the ORACLE_BASE directory, then enter the following commands to create the required settings:

   • Bourne, Bash, or Korn shell:

     $ ORACLE_SID=OraDB11g+ASM
     $ export ORACLE_SID
     $ ORACLE_HOME=/u01/app/oracle/product/11.1.0/asm
     $ export ORACLE_HOME
     
     

   • C shell:

     % setenv ORACLE_SID OraDB11g+ASM
     % setenv ORACLE_HOME /u01/app/oracle/product/11.1.0/asm
     
     

3. By using SQL*Plus, connect to the Automatic Storage Management instance as the SYS user with SYSDBA privilege and start the instance if necessary:

   # $ORACLE_HOME/bin/sqlplus 
   SQL> CONNECT SYS as SYSDBA
   Enter password: SYS_password 
   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.

2.12.4 Step 3: Creating DAS or SAN Disk Partitions for Automatic Storage Management

In order to use a DAS or SAN disk in Automatic Storage Management, the disk must have a partition table. Oracle recommends creating exactly one partition for each disk containing the entire disk.

2.12.5 Step 4: Configuring Disks for Automatic Storage Management

Oracle provides an Automatic Storage Management library driver that you can use to simplify the configuration and management of the disk devices that you want to use with Automatic Storage Management. A disk that is configured for Automatic Storage Management is known as a candidate disk.

If you intend to use Automatic Storage Management for database storage on Linux, then Oracle recommends that you install the Automatic Storage Management library driver and associated utilities and use them to configure the devices that you want to include in an Automatic Storage Management disk group.

configure

# /etc/init.d/oracleasm configure

enable
disable

# /etc/init.d/oracleasm enable

start
stop
restart

# /etc/init.d/oracleasm restart

createdisk

# /etc/init.d/oracleasm createdisk DISKNAME devicename

deletedisk

# /etc/init.d/oracleasm deletedisk DISKNAME

querydisk

# /etc/init.d/oracleasm querydisk {DISKNAME | devicename}

listdisks

# /etc/init.d/oracleasm listdisks

scandisks

# /etc/init.d/oracleasm scandisks