What files can be stored in the ASM Diskgroup?

You can store the following file types in ASM diskgroups:

Table of Contents

Datafiles.
Control files.
Online redo logs.
Archive logs.
Flashback logs.
SPFILEs.
RMAN backups.
Temporary datafiles.

What is an ASM instance?

The Oracle ASM instance manages the metadata and provides space allocation for the Oracle ASM files. When a database instance creates or opens an Oracle ASM file, it communicates those requests to the Oracle ASM instance.

What is Lun in Oracle ASM?

Logical Unit Number (LUN) A LUN is a disk presented to a computer system by a storage array. Oracle recommends that you use hardware RAID functionality to create LUNs. Storage hardware RAID 0+1 or RAID5, and other RAID configurations, can be provided to Oracle ASM as Oracle ASM disks.

What is ASM power limit?

The ASM_POWER_LIMIT initialization parameter specifies the default power for disk rebalancing in a disk group. The range of values is 0 to 1024 . The default value is 1 . A value of 0 disables rebalancing.

What is the use of extent in Oracle?

An extent is a logical unit of database storage space allocation made up of a number of contiguous data blocks. One or more extents in turn make up a segment. When the existing space in a segment is completely used, Oracle allocates a new extent for the segment.

Which of the following parameters are required for an ASM instance?

The main parameters for ASM include asm_diskgroups, asm_diskstring, asm_power_limit and asm_preferred_read_failure_groups. instance_type: This is normally set to instance_type=ASM, but the default is non-ASM where instance_type= rdbms.

How do I know my ASM LUN size?

SQL:ASM>select name,total_mb,free_mb,state from v$asm_diskgroup; ASMCMD tool can also be used to find the free space. du -Displays the total disk space occupied by ASM files in the specified ASM directory and all its subdirectories, recursively.

How do I manually start an ASM?

Startup and shutdown the Oracle ASM instance

Set the default Oracle_home environment variable to grid home where ASM is installed. EXPORT ORACLE_HOME=/up1/grid/12.2.0/dbhome_1.
Connect with sqlplus. SQLPLUS / as sysasm.
Start up the Oracle ASM Instance. SQL> STARTUP.
Check the spfile location or otherwise set it with.

What is Lun in ASM?

What is Pctused and Pctfree in Oracle?

The PCTFREE and PCTUSED parameters are physical attributes that can be specified when a schema object is created or altered. These parameters allow you to control the use of the free space within a data block. This free space is available for inserts and updates of rows of data.

How do I check ASM background process?

ASMB – ASM Background Process.
RBAL – ASM Rebalance Master Process.
ARBn – ASM Rebalance Process.
DBWR – Database Writer Process.
SMON – System Monitor Process.
CKPT – Checkpoint Process.
PSP0 – Process Spawner Process.
GMON – ASM Disk Group Monitor Process.

Where is the disk path in ASM?

In Linux, ASMLib provides the wrapper for managing the ASM disks. To identify the underlying physical device that the ASM disk point to, you can use the oracleasm querydisk command. The querydisk option will list the major and minor numbers that can be used to match the physical device.

What are Oracle ASM disks?

Oracle ASM disks are the storage devices that are provisioned to Oracle ASM disk groups. Examples of Oracle ASM disks include: When you add a disk to a disk group, you can assign an Oracle ASM disk name or Oracle ASM assigns the Oracle ASM disk name automatically.

How do I mount a disk group in Oracle?

A disk group must be mounted by a local Oracle ASM instance before database instances can access the files in the disk group. Mounting the disk group requires discovering all of the disks and locating the files in the disk group that is being mounted. You can explicitly dismount a disk group.

How do I drop a disk in Oracle ASM?

Use the Oracle ASM disk name to drop a disk, not the discovery string device name. If an error occurs while writing to a disk, then Oracle ASM drops the disk automatically. For more information about altering disk group membership, see “Altering Disk Groups”.

What is allocation unit in Oracle ASM?

Every Oracle ASM disk is divided into allocation units (AU). An allocation unit is the fundamental unit of allocation within a disk group. A file extent consists of one or more allocation units. An Oracle ASM file consists of one or more file extents.