ASM rpm installation and configuration

Automatic Storage Management (ASM)
ASM was a new storage option introduced with Oracle Database 10gR1 that provides the services of a filesystem, logical volume manager, and software RAID in a platform-independent manner. ASM can stripe and mirror your disks, allow disks to be added or removed while the database is under load, and automatically balance I/O to remove “hot spots.” It also supports direct and asynchronous I/O and implements the Oracle Data Manager API (simplified I/O system call interface) introduced in Oracle9i.
ASM is not a general-purpose filesystem and can be used only for Oracle data files, redo logs, control files, and flash recovery area. Files in ASM can be created and named automatically by the database (by use of the Oracle Managed Files feature) or manually by the DBA. Because the files stored in ASM are not accessible to the operating system, the only way to perform backup and recovery operations on databases that use ASM files is through Recovery Manager (RMAN).
ASM is implemented as a separate Oracle instance that must be up if other databases are to be able to access it. Memory requirements for ASM are light: only 64 MB for most systems.

Installing ASM

On Linux platforms, ASM can use raw devices or devices managed via the ASMLib interface. Oracle recommends ASMLib over raw devices for ease-of-use and performance reasons. ASMLib 2.0 is available for free download from OTN. This section walks through the process of configuring a simple ASM instance by using ASMLib 2.0 and building a database that uses ASM for disk storage.

Determine Which Version of ASMLib You Need
ASMLib 2.0 is delivered as a set of three Linux packages:
oracleasmlib-2.0 – the ASM libraries
oracleasm-support-2.0 – utilities needed to administer ASMLib
oracleasm – a kernel module for the ASM library
Each Linux distribution has its own set of ASMLib 2.0 packages, and within each distribution, each kernel version has a corresponding oracleasm package. The following paragraphs describe how to determine which set of packages you need.
First, determine which kernel you are using by logging in as root and running the following command:

#uname -rm

Ex:
# uname -rm
2.6.9-22.ELsmp i686

The example shows that this is a 2.6.9-22 kernel for an SMP (multiprocessor) box using Intel i686 CPUs.

Use this information to find the correct ASMLib packages on OTN:

Point your Web browser to

http://www.oracle.com/technetwork/server-storage/linux/downloads/rhel5-084877.html
Select the link for your version of Linux.
Download the oracleasmlib and oracleasm-support packages for your version of Linux
Download the oracleasm package corresponding to your kernel. In the example above, the oracleasm-2.6.9-22.ELsmp-2.0.0-1.i686.rpm package was used.
Next, install the packages by executing the following command as root:

 
#rpm -Uvh oracleasm-kernel_version-asmlib_version.cpu_type.rpm \
oracleasmlib-asmlib_version.cpu_type.rpm \
oracleasm-support-asmlib_version.cpu_type.rpm
Ex:
# rpm -Uvh \
> oracleasm-2.6.9-22.ELsmp-2.0.0-1.i686.rpm \
> oracleasmlib-2.0.1-1.i386.rpm \
> oracleasm-support-2.0.1-1.i386.rpm
Preparing... ########################################### [100%]
 1:oracleasm-support ########################################### [ 33%]
 2:oracleasm-2.6.9-22.ELsm########################################### [ 67%]
 3:oracleasmlib ########################################### [100%]

Configuring ASMLib

Before using ASMLib, you must run a configuration script to prepare the driver. Run the following command as root, and answer the prompts as shown in the example below. Run this on each node in the cluster.

# /etc/init.d/oracleasm configure
Configuring the Oracle ASM library driver.
This will configure the on-boot properties of the Oracle ASM library driver. The following questions will determine whether the driver is loaded on boot and what permissions it will have. The current valueswill be shown in brackets ('[]'). Hitting <ENTER> without typing an
answer will keep that current value. Ctrl-C will abort.
Default user to own the driver interface []: oracle
Default group to own the driver interface []: dba
Start Oracle ASM library driver on boot (y/n) [n]: y
Fix permissions of Oracle ASM disks on boot (y/n) [y]: y
Writing Oracle ASM library driver configuration: [ OK ]
Creating /dev/oracleasm mount point: [ OK ]
Loading module "oracleasm": [ OK ]
Mounting ASMlib driver filesystem: [ OK ]
Scanning system for ASM disks: [ OK ]

Next you tell the ASM driver which disks you want it to use. Oracle recommends that each disk contain a single partition for the entire disk. See Partitioning the Disks at the beginning of this section for an example of creating disk partitions.

You mark disks for use by ASMLib by running the following command as root from one of the cluster nodes:

/etc/init.d/oracleasm createdisk DISK_NAME device_name
Tip: Enter the DISK_NAME in UPPERCASE letters.

Ex:
# /etc/init.d/oracleasm createdisk VOL1 /dev/sdb1
Marking disk "/dev/sdb1" as an ASM disk: [ OK ]
# /etc/init.d/oracleasm createdisk VOL1 /dev/sdc1
Marking disk "/dev/sdc1" as an ASM disk: [ OK ]
# /etc/init.d/oracleasm createdisk VOL1 /dev/sdd1
Marking disk "/dev/sdd1" as an ASM disk: [ OK ]
Verify that ASMLib has marked the disks:
# /etc/init.d/oracleasm listdisks
VOL1
VOL2
VOL3

On all other cluster nodes, run the following command as root to scan for configured ASMLib disks:
/etc/init.d/oracleasm scandisks

About Sher khan

Senior Oracle DBA, Oracle 10g and 11g OCE and OCS, Oracle 11g OPN certified Specialist, OCP Certified in Oracle 9i,10g and 11g. I am working in Oracle technology since 2004. Currently working in U.A.E Email: sher487@hotmail.com
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