Table of Contents
How do you rebalance in Diskgroup?
You can manually rebalance the files in a disk group using the REBALANCE clause of the ALTER DISKGROUP statement. This would normally not be required, because Oracle ASM automatically rebalances disk groups when their configuration changes.
What is ASM rebalancing?
Oracle ASM rebalancing operations are controlled by the size of the disks in a disk group. Oracle ASM automatically initiates a rebalance after storage configuration changes, such as when you add, drop, or resize disks. The power setting parameter determines the speed with which rebalancing operations occur.
How do I stop ASM rebalancing?
ASM set to less than 11.2. 0.2, the operational range of values is 0 to 11 inclusive. Specifying 0 for the POWER in the ALTER DISKGROUP REBALANCE command will stop the current rebalance operation (unless you hit bug 7257618).
How can I speed up my ASM rebalance?
ASM Rebalance Too Slow? 3 Tips To Improve Rebalance Times
- Don’t Overbalance.
- Power Limit Goes Up To 1024.
- Avoid The Compact Phase (for Flash Storage Systems)
How do I check ASM Diskgroup attributes?
You can display disk group attributes with the V$ASM_ATTRIBUTE view and the ASMCMD lsattr command. Disk group attributes can be set with the ATTRIBUTE clause of the ALTER DISKGROUP or CREATE DISKGROUP SQL statement and the ASMCMD setattr and mkdg commands.
What is Lun in 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 the use of ASM_POWER_LIMIT?
ASM_POWER_LIMIT specifies the maximum power on an Oracle ASM instance for disk rebalancing. The higher the limit, the faster rebalancing will complete. Lower values will take longer, but consume fewer processing and I/O resources.
What is power limit in ASM?
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.
How do I change ASM Diskgroup compatibility?
The disk group compatibility attributes for existing disk groups can be altered using the SET ATTRIBUTE clause to the ALTER DISKGROUP command. ALTER DISKGROUP data SET ATTRIBUTE ‘compatible. asm’ = ‘11.1’; ALTER DISKGROUP data SET ATTRIBUTE ‘compatible.
How do I know if ASM is compatible with Diskgroup?
Check the compatibility of ASM diskgroup in Oracle
- Check the compatibility of a ASM diskgroup. SELECT name AS diskgroup, substr(compatibility,1,12) AS asm_compat,
- Check the ASM attribute. column value for a20.
- Create diskgroup defines tha attribute.
- Alter command only used to increased value.
What files can be stored in the ASM Diskgroup?
You can store the following file types in ASM diskgroups:
- Datafiles.
- Control files.
- Online redo logs.
- Archive logs.
- Flashback logs.
- SPFILEs.
- RMAN backups.
- Temporary datafiles.
How do I add a LUN to ASM Diskgroup?
- Create ASM disk. Get the Lun name from storage team. Lun Name – /dev/sda1.
- Check the ASM Disks, Check the newly added disk, $sudo oracleasm listdisks.
- Create the ASM Diskgroup. $sqlplus / as sysasm.
- Check the rebalance status. $sqlplus / as sysasm.
- Check the newly added disk in ASM Diskgroup.
What is Failgroup in ASM Oracle?
Failure groups are used to store mirror copies of data. When Oracle ASM allocates an extent for a normal redundancy file, Oracle ASM allocates a primary copy and a secondary copy. Oracle ASM chooses the disk on which to store the secondary copy so that it is in a different failure group than the primary copy.
What is redundancy in ASM?
Normal redundancy. Oracle ASM provides two-way mirroring by default, which means that all files are mirrored so that there are two copies of every extent. A loss of one Oracle ASM disk is tolerated. You can optionally choose three-way or unprotected mirroring.
What is failure group in ASM Oracle?
Failure Groups are used to specify placement of mirrored copies so that each copy is on a disk in different Failure Groups. The simultaneous failure of all disks in a Failure Group does not result in data loss. The customer defines the Failure Groups for a Diskgroup when they create an Oracle ASM Diskgroup.