ASM Commands

Summary of ASM Commands:
This section describes each individual ASMCMD command in detail:

cd: Changes the current directory to the specified directory.
du:Displays the total disk space occupied by ASM files in the specified ASM directory and all its subdirectories, recursively.
exit:Exits ASMCMD.
find:Lists the paths of all occurrences of the specified name (with wildcards) under the specified directory.
help:Displays the syntax and description of ASMCMD commands.
ls:Lists the contents of an ASM directory, the attributes of the specified file, or the names and attributes of all disk groups.
lsct:Lists information about current ASM clients.
lsdg:Lists all disk groups and their attributes.
mkalias:Creates an alias for a system-generated filename.
mkdir:Creates ASM directories.
pwd:Displays the path of the current ASM directory.
rm:Deletes the specified ASM files or directories.
rmalias:Deletes the specified alias, retaining the file that the alias points to.

Refer the below URL for more details on asmcmd for 10GR2:
http://www.mcs.csueastbay.edu/support/oracle/doc/10.2/server.102/b14215/asm_util.htm#table

Refer the below URL for more details on asmcmd for 11G Release 1:
http://download.oracle.com/docs/cd/B28359_01/server.111/b31107/asm_util.htm#table

ASM Instance

Manually Creating an ASM Instance:
Automatic Storage Management (ASM) is a new feature in Oracle10g that alleviates the DBA from having to manually manage and tune disks used by Oracle databases. ASM provides the DBA with a file system and volume manager that makes use of an Oracle instance (referred to as an ASM instance) and can be managed using either SQL or Oracle Enterprise Manager.

Only one ASM instance is required per node. The same ASM instance can manage ASM storage for all 10g databases running on the node.

When the DBA installs the Oracle10g software and creates a new database, creating an ASM instance is a snap. The DBCA provides a simple check box and an easy wizard to create an ASM instance as well as an Oracle database that makes use of the new ASM instance for ASM storage. But, what happens when the DBA is migrating to Oracle10g or didn't opt to use ASM when a 10g database was first created. The DBA will need to know how to manually create an ASM instance and that is what this article provides.

1. Overview
2. Configuring Oracle Cluster Synchronization Services (CSS)
3. Creating the ASM Instance
4. Identify RAW Devices
5. Starting the ASM Instance
6. Verify RAW / Logical Disk Are Discovered
7. Creating Disk Groups
8. Using Disk Groups
9. Startup Scripts

Go through the below link to cover all the above topic.

http://www.idevelopment.info/data/Oracle/DBA_tips/Automatic_Storage_Management/ASM_10.shtml

Note: Automatic Storage Management (ASM) requires the use of Oracle Cluster Synchronization Services (CSS), and as such, CSS must be configured and running before attempting to use ASM. The CSS service is required to enable synchronization between an ASM instance and the database instances that rely on it for database file storage.

With Oracle10g R1, CSS was always configured regardless of whether you chose to configure ASM or not. On the Linux / UNIX platform, CSS was installed and configured via the root.sh script. This caused a lot of problems since many did not know what this process was, and for most of them, didn't want the CSS process running since they were not using ASM.

Oracle listened carefully to the concerns (and strongly worded complaints) about the CSS process and in Oracle10g R2, will only configure this process when it is absolutely necessary. In Oracle10g R2, for example, if you don't choose to configure an ASM stand-alone instance or if you don't choose to configure a database that uses ASM storage, Oracle will not automatically configure CSS in the root.sh script.

In the case where the CSS process is not configured to run on the node (see above), you can make use of the $ORACLE_HOME/bin/localconfig script in Linux / UNIX or %ORACLE_HOME%\bin\localconfig.bat batch file in Windows. For example in Linux, run the following command as root to configure CSS outside of the root.sh script after the fact:

Convert Single Instance Database to RAC and ASM

Convert a Single Instance Database to Oracle RAC 10g on RHEL3:

Learn how to convert a single-instance database to Oracle Real Application Clusters (RAC) 10g on Red Hat Enterprise Linux 3 (RHEL3), step by step.
Contents
Overview
Step 1: Preliminary Installation
Step 2: Migrate Your Database to ASM
Step 3: Install Cluster Ready Services (CRS) Software
Step 4: Install Oracle RAC Software
Step 5: Post Installation
Step 6: Test Transparent Application Failover (TAF)Conclusion

Download for this article:
Oracle Database 10g Enterprise Edition and Clusterware for Linux x86
Oracle ASMlib Drivers

For those with limited hands-on experience, implementing Oracle RAC 10g can be an intimidating prospect. But it doesn't have to be that way.

In this guide, I'll provide the precise procedures for converting a single-instance Oracle 10g database to Oracle RAC on RHEL3. We'll use Oracle Automatic Storage Management (ASM), an integrated file system and a volume management solution built into the Oracle database kernel, for RAC database storage because it simplifies database storage management tasks while offering storage reliability and performance.

To summarize on a very high level, there are several ways to convert your database to RAC. If the database is small, you can consider installing a new RAC database on ASM and export/import your data from your current database to the RAC database. For a larger database, the preferred method would be to use RMAN to migrate the database files over to ASM.

The method demonstrated here is a two-phase approach:

first, migrating the data to ASM, and
second, converting the single-instance database to RAC.

If you are new to ASM, I would recommend taking this migration path to get familiar with ASM before leaping into ASM and RAC at the same time. (For more information about Oracle ASM, visit the Oracle ASM Product Center or refer to the documentation.)

This guide requires a basic understanding of RAC architecture and some familiarity with managing and administering Oracle Database and Red Hat Enterprise Linux. Refer to the documentation for details.

The detailed stepwise guidance is available at the below URL:
http://www.oracle.com/technology/pub/articles/chan_sing2rac_install.html

The above URL holds a beautiful document to migrate a single instance database from Cluster file system to ASM and to RAC.

Automatic Storage Management

ASM using ASMLib and Raw Devices:
--------------------------------------------
This is a beutiful document which covers almost the full setup for an ASM (Automatic Storage Management ) environment. For your reference it covers the following:

• Introduction
• Partition the Disks
• ASMLib Installation
• Raw Device Setup
• ASM Creation
• Database Creation
• Switching from Raw Devices to ASMLib
• Switching from ASMLib to Raw Devices
• Performance Comparison

http://www.oracle-base.com/articles/10g/ASMUsingASMLibAndRawDevices.php#raw_device_setup

Automatic Storage Management (ASM) in Oracle Database 10g:
-------------------------------------------------------------- ---------------
This document covers a small part of Oracle Automatic Storage Management (ASM) Commands to Manage an ASM instance and database. Also You will get a quick idea how to Migrate a Oracle single instance database to ASM using RMAN.

http://www.oracle-base.com/articles/10g/AutomaticStorageManagement10g.php

Commanding ASM (Automatic Storage Management)
----------------------------------------------------------
Access, transfer, and administer ASM files without SQL commands.

Oracle Database 10g Release 1 introduced Automatic Storage Management (ASM), a new framework for managing Oracle database files. ASM provided a foundation for highly efficient storage management with kernelized asynchronous I/O, direct I/O, redundancy, striping, and an easy way to manage storage. ASM includes volume management functionality similar to that of a generic logical volume manager (LVM).

Managing ASM through SQL interfaces in Oracle Database 10g Release 1 posed a challenge for system administrators who were not very familiar with SQL and preferred a more conventional command-line interface. In Oracle Database 10g Release 2, you have an option to manage the ASM files by using ASMCMD—a powerful and easy-to-use command-line tool.

In Oracle Database 10g Release 1, ASM disk groups are not visible outside the database for regular file system administration tasks such as copying and creating directories. In Oracle Database 10g Release 2, however, you can transfer the files from ASM to locations outside of the disk groups via FTP and through a Web browser using HTTP.

This article shows you how to use these enhancements in ASM to accomplish everyday tasks.
http://www.oracle.com/technology/oramag/oracle/06-mar/o26asm.html

Set asmcmd prompt display:
You can invoke asmcmd with the -p option to display the current path, very similar to the UNIX/Linux.
PS1="
`hostname`*\${ORACLE_SID}-\${PWD}
>"
export PS1

fred:/u01/app/oracle/admin>

asmcmd command line history:
The asmcmd utility does not provide a command history with the up-arrow key. With rlwrapinstalled, this can be fixed by adding the following entry to the ~oracle/.bashrc file:

alias asmcmd='rlwrap asmcmd'

Automatic Storage Manager (ASM) Enhancements in Oracle Database 11g Release 1:
----------------------------------------------------------------------------
http://www.oracle-base.com/articles/11g/AsmEnhancements_11gR1.php

SQL Help for ASM (Automatic Storage Management):
--------------------------------------------------------------
Create Diskgroup:
Use the CREATE DISKGROUP clause to create a collection of disks. Oracle Database manages a disk group as a logical unit and evenly spreads each file across the disks to balance I/O. Oracle Database also automatically distributes database files across all available disks in disk groups and rebalances storage automatically whenever the storage configuration changes.

This statement creates a disk group, assigns one or more disks to the disk group, and mounts the disk group for the first time. If you want Automatic Storage Management to mount the disk group automatically in subsequent instances, you must add the disk group name to the value of the ASM_DISKGROUPS initialization parameter in the initialization parameter file. If you use an SPFILE, then the disk group is added to the initialization parameter automatically.
http://download.oracle.com/docs/cd/B19306_01/server.102/b14200/statements_5008.htm#i2153287

Alter Diskgroup:
The ALTER DISKGROUP statement lets you perform a number of operations on a disk group or on the disks in a disk group.
http://download.oracle.com/docs/cd/B19306_01/server.102/b14200/statements_1006.htm#i2166968

Drop Diskgroup:
The DROP DISKGROUP statement lets you drop an Automatic Storage Management disk group along with all the files in the disk group. Automatic Storage Management first ensures that no files in the disk group are open. It then drops the disk group and all its member disks and clears the disk header.
http://download.oracle.com/docs/cd/B19306_01/server.102/b14200/statements_8013.htm#i2152629