How to use Oracle ASM

Why is Oracle ASM Important?

Simplified Storage Management: ASM eliminates the need for third-party volume managers and file systems, streamlining storage administration tasks.
High Performance: ASM is optimized for Oracle database files, providing efficient striping and mirroring to improve I/O performance and reliability.
Automatic Rebalancing: ASM automatically redistributes data across disks to maintain optimal performance and capacity utilization.
Integration with Oracle Clusterware: ASM integrates seamlessly with Oracle Clusterware to provide high availability and scalability for clustered database environments.

Basic Concepts:

Disk Groups: ASM organizes physical disks into disk groups, which serve as the storage containers for database files. Each disk group consists of one or more disks with similar characteristics (e.g., size, performance).
ASM Instances: ASM instances manage the storage resources within a database server. These instances are separate from the database instances but are tightly integrated with them.
ASM Files: ASM files include data files, control files, redo log files, and archive log files stored within ASM disk groups. These files are accessed directly by the database instances.

Basic Operations:

CREATE DISKGROUP data_diskgroup EXTERNAL REDUNDANCY DISK ‘/dev/sd*’;

ALTER DISKGROUP data_diskgroup ADD DISK ‘/dev/sd*’;

CREATE TABLESPACE my_ts DATAFILE ‘+data_diskgroup’ SIZE 100M;

Advanced Operations:

Mirroring and Striping:Configure disk groups for mirroring (redundancy) and striping (performance) using redundancy levels (NORMAL, HIGH, or EXTERNAL) and stripe sizes.
Automatic Rebalance:ASM automatically rebalances data across disks in a disk group when new disks are added or removed, ensuring even data distribution and optimal performance.
Failure Recovery:ASM automatically detects and recovers from disk failures by relocating data to surviving disks and initiating disk repair operations.

Monitoring and Management:

ASM Views:Monitor ASM disk groups, disks, and files using views such as V$ASM_DISKGROUP, V$ASM_DISK, and V$ASM_FILE.
ASM Command-Line Interface (ASMCMD):Use ASMCMD, a command-line utility provided by Oracle, to perform various management tasks such as listing disk groups, adding disks, and managing ASM files.

Security Considerations:

ASM Privileges:Grant appropriate privileges (e.g., SYSASM) to users who need to administer ASM instances and disk groups.
Disk Group Encryption:Implement disk group encryption to protect sensitive data stored within ASM disk groups.

Permanent