disk_repair_time in ASM

 

SELECT SUBSTR(dg.name,1,12) AS diskgroup, SUBSTR(a.name,1,24) AS name,

SUBSTR(a.value,1,24) AS value, read_only FROM V$ASM_DISKGROUP dg,

V$ASM_ATTRIBUTE a WHERE dg.name = 'DATA01' AND dg.group_number = a.group_number

AND a.name NOT LIKE '%template%';

DISKGROUP    NAME                           VALUE                READ_ON

------------ ------------------------------ -------------------- -------

DATA01       idp.type                       dynamic              N

DATA01       idp.boundary                   auto                 N

DATA01       vam_migration_done             false                Y

DATA01       scrub_content_check_in_r       FALSE                N

DATA01       scrub_metadata.enabled         TRUE                 N

DATA01       scrub_async_limit              1                    N

DATA01       content_hardcheck.enable       FALSE                N

DATA01       maxblkdump_content.check       3                    N

DATA01       maxerr_content.check           1048576              N

DATA01       maxdump_content.check          32                   N

DATA01       access_control.umask           066                  N

DATA01       access_control.enabled         FALSE                N

DATA01       cell.sparse_dg                 allnonsparse         N

DATA01       cell.smart_scan_capable        FALSE                N

DATA01       compatible.rdbms               10.1.0.0.0           N

DATA01       compatible.asm                 19.0.0.0.0           N

DATA01       appliance._partnering_ty       GENERIC              Y

DATA01       au_size                        4194304              Y

DATA01       content.check                  FALSE                N

DATA01       content.type                   data                 N

DATA01       logical_sector_size            512                  N

DATA01       sector_size                    512                  N

DATA01       ate_conversion_done            true                 Y

DATA01       preferred_read.enabled         FALSE                N

DATA01       thin_provisioned               FALSE                N

DATA01       failgroup_repair_time          24.0h                N

DATA01       phys_meta_replicated           true                 Y

DATA01       disk_repair_time               12.0h                N

28 rows selected.

The disk_repair_time attribute, as seen in your output, is set to 12.0 hours for the DATA01 disk group. This value defines how long Oracle ASM waits for a disk to be brought back online after being taken offline. If the disk is not repaired and brought online within this time frame, ASM automatically drops the disk from the disk group.

Here’s what this output tells us:

1. Attribute Name: disk_repair_time

   • Represents the grace period allowed for repairing a failed disk.

2. Value: 12.0h

   • Indicates that the disk has 12 hours to be repaired and reintroduced into the disk group.

3. READ_ON:

• The "N" under this column indicates that the disk_repair_time attribute is not readable by ASM instances other than the current one.

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Explanation:

When a disk is marked offline, ASM starts the timer for the period defined by disk_repair_time. During this time:

• The disk remains part of the disk group.
• ASM does not rebalance data, as it assumes the disk will come back online.
• If the disk does not come back within the defined time, it is permanently dropped from the disk group.

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How to Modify disk_repair_time:

If you need to change this value for a specific disk group, use the following SQL command:

ALTER DISKGROUP DATA01 SET ATTRIBUTE 'disk_repair_time' = '24.0h';

This sets the disk_repair_time to 24 hours for the DATA01 disk group.

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Verification Command:

To verify the current disk_repair_time:

SELECT name, value
FROM v$asm_attribute
WHERE name = 'disk_repair_time';

This query will return the current disk_repair_time setting for all disk groups.

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