1 Automatic Storage Management (ASM) Policies

This chapter provides the following information for each of the Automatic Storage Management (ASM) policies:

Brief description of the policy
Summary of the policy's main properties
Default values for the policy: parameters with their default values and objects excluded by default
Impact of the policy violation
Action to perform when the violation occurs

The Automatic Storage Management target only has storage policies.

1.1 Disk Group Contains Disks of Significantly Different Sizes

This policy checks the disk group for disks with disk sizes which vary by more than 5%.

Policy Summary

The following table lists the policy's main properties.

Severity	Category	Target Type	Versions Affected	Policy Rule Evaluation^Foot 1	Automatically Enabled?	Alert Message
Warning	Storage	Database Instance	Oracle Server 10g Release 1 or later	The underlying metric has a collection frequency of once every 7 days.	Yes	Disk Group %DISK_GROUP_NAME% contains disks of significantly different sizes. For balanced I/O and optimal performance, disks in a given disk group should have similar size and performance characteristics.

^Footnote 1The policy rule is evaluated each time its underlying osm_diskGroup_Policies metric is collected.

Defaults

Parameters and Their Default Values

Parameter default values are dependent on the version of the Oracle Database target. Refer to the Oracle Database documentation for that version of the database target to learn about the parameters and their default values.

Objects Excluded by Default

Not Applicable

Impact of Violation

Disks in a disk group should have sizes within 5% of each other, unless data migration is in progress. Automatic Storage Management distributes data uniformly proportional to the size of the disks. For balanced I/O and optimal performance, disks in a given disk group should have similar size and performance characteristics.

Action

Remove, replace, or resize disks in the disk group so the size difference between disks is less than 5%.

1.2 Disk Group Contains Disks with Different Redundancy Attributes

This policy checks the disk group for disks that have different redundancy attributes

Policy Summary

The following table lists the policy's main properties.

Severity	Category	Target Type	Versions Affected	Policy Rule Evaluation^Foot 1	Automatically Enabled?	Alert Message
Warning	Storage	Database Instance	Oracle Server 10g Release 1 or later	The underlying metric has a collection frequency of once every 7 days.	Yes	Disk Group %DISK_GROUP_NAME% contains disks with different redundancy attributes. This may offer inconsistent levels of data protection.

^Footnote 1The policy rule is evaluated each time its underlying osm_diskGroup_Policies metric is collected.

Defaults

Parameters and Their Default Values

Objects Excluded by Default

Not Applicable

Impact of Violation

Disks in the same disk group with different redundancy attributes may offer inconsistent levels of data protection.

Action

Move disks with different redundancy attributes into separate disk groups.

1.3 Disk Group Depends on External Redundancy and Has Unprotected Disks

This policy checks the disk group, which depends on external redundancy, for disks that are not mirrored or parity protected.

Policy Summary

The following table lists the policy's main properties.

Severity	Category	Target Type	Versions Affected	Policy Rule Evaluation^Foot 1	Automatically Enabled?	Alert Message
Warning	Storage	Database Instance	Oracle Server 10g Release 1 or later	The underlying metric has a collection frequency of once every 7 days.	Yes	Disk Group %DISK_GROUP_NAME% depends on external redundancy and has disks that are not mirrored or parity protected.

^Footnote 1The policy rule is evaluated each time its underlying osm_diskGroup_Policies metric is collected.

Defaults

Parameters and Their Default Values

Objects Excluded by Default

Not Applicable

Impact of Violation

Data loss can occur if the disk group depends on external redundancy and disks are not mirrored or parity protected.

Action

Replace problem disks with mirrored or parity protected disks, or move unprotected disks into a disk group with NORMAL or HIGH redundancy.

1.4 Disk Group with NORMAL or HIGH Redundancy Has Mirrored or Parity Protected Disks

This policy has detected that a disk group with normal or high redundancy has mirrored or parity protected disks.

Policy Summary

The following table lists the policy's main properties.

Severity	Category	Target Type	Versions Affected	Policy Rule Evaluation^Foot 1	Automatically Enabled?	Alert Message
Warning	Storage	Database Instance	Oracle Server 10g Release 1 or later	The underlying metric has a collection frequency of once every 7 days.	Yes	NORMAL or HIGH redundancy disk group %DISK_GROUP_NAME% has disks that are mirrored or parity protected. Disk resources are wasted, and performance may be unnecessarily affected when both a disk and its owning disk group are providing data redundancy.

^Footnote 1The policy rule is evaluated each time its underlying osm_diskGroup_Policies metric is collected.

Defaults

Parameters and Their Default Values

Objects Excluded by Default

Not Applicable

Impact of Violation

Disk resources are wasted, and performance may be unnecessarily affected when both a disk and its owning disk group are providing data redundancy.

Action

Replace disks in the NORMAL or HIGH redundancy disk group with unprotected disks.