7 Administering Oracle ASM with Oracle Enterprise Manager

You can create disk groups with Oracle Enterprise Manager.

You can create additional Oracle ASM disk groups to:

• Have disk groups with different redundancy levels (normal, high, or external), depending on availability requirements and storage system capabilities.

• Separate different classes of storage, such as SCSI drives and SATA drives, into different disk groups. Disks in a disk group should have similar size and performance characteristics.

• Store the fast recovery area in a separate disk group from the database.

To create a disk group:

1. Access the Oracle Automatic Storage Management home page.

2. Click the Disk Groups link at the top of the page to display the Disk Groups property page.

3. If you are not logged in, then the Log In page appears and you should log in as the SYS user, connecting as SYSASM. Provide the SYS password for the Oracle ASM instance. This password was set up when the Oracle ASM instance was created.

4. Click Create and Oracle Enterprise Manager displays a Create Disk Group page. The Create Disk Group page displays a list of Oracle ASM disks that are available to be added to a disk group. This includes disks with a header status of CANDIDATE, PROVISIONED, or FORMER, and so on.

5. To display not only disks that are available to be added to a disk group, but all Oracle ASM disks, including disks that belong to a disk group (header status = MEMBER), select All Disks from the Select Member Disks list.

   The page is re-displayed with the complete list of Oracle ASM disks that were discovered by the Oracle ASM instance.

6. Enter the disk name, select a redundancy type (high, normal, or external), and optionally, you can enter a failure group name.

7. Select disks as follows:

   • Select the box to the left of each disk to be included in the new disk group.

   • Optionally, you can enter a disk name, the size of the disk for Oracle ASM to use, and the failure group name.

   • To force the inclusion of a disk in the disk group, select the Force Usage box for that disk.

     Caution:

     Selecting the Force Usage box causes the disk to be added to the new disk group even if the disk belongs to another disk group and has valid database data. The existing data is then lost. You must be certain that you are selecting a disk that can legitimately be added to the disk group.

8. Specify a Disk Compatibility value for the disk group to enable your system to use the latest Oracle ASM features.

   Note:

   You cannot reverse the setting of a disk group compatibility value.

9. Click OK to create the disk group or click Cancel to stop the disk group creation operation. You can also click Show SQL to show the SQL statements that the disk group creation operation uses.

You can add disks to disk groups with Oracle Enterprise Manager.

You can add disks to a disk group to increase the storage space in a disk group. If you add multiple disks in a single operation, then Oracle ASM rebalances the disk group to evenly distribute the data on all disks, including the newly added disks.

You can control the power of a rebalance operation with the setting of the Rebalance Power. The higher the number, the faster the rebalance operation completes. Lower numbers cause rebalancing to take longer, but consume fewer processing and I/O resources. This leaves these resources available for the database. The default value of 1 minimizes disruption to the database.

A value of 0 blocks the rebalance operation. Manual or automatic rebalance can then occur later. You might want to postpone rebalancing until there are fewer demands on the database, or when you have completed all of your disk group changes.

To add one or more disks to a disk group:

1. Access the Oracle Automatic Storage Management home page.

2. Click the Disk Groups link to display the Disk Groups property page.

3. If the Oracle ASM Login page appears, then log in as the SYS user, connecting as SYSASM. Provide the SYS password for the Oracle ASM instance. This password was set up when the Oracle ASM instance was created.

4. Click a link in the Name column to select the disk group to which you want to add disks. The Disk Group page appears, displaying a list of disks that are in the disk group.

5. Click Add and Oracle Enterprise Manager displays the Add Disks page. This page displays a list of Oracle ASM disks that are available to be added to the disk group. This includes disks with the header status of CANDIDATE, PROVISIONED, or FORMER, and so on.

6. To display not only disks that are available to be added to a disk group, but all of the Oracle ASM disks, including disks that belong to a disk group (header status = MEMBER), select All Disks from the Select Member Disks drop-down list on the right hand side of the page. Oracle Enterprise Manager re-displays the page with the complete list of Oracle ASM disks that were discovered by the Oracle ASM instance.

7. Optionally change the rebalance power by selecting a value from the Rebalance Power list.

8. Select disks as follows:

   • Check the box to the left of each disk to be added to the disk group.

   • To force the inclusion of a disk in the disk group, select the Force Reuse box in the right-most column.

     Caution:

     The Force Reuse box causes the disk to be added to the disk group even if the disk belongs to another disk group and has valid database data. The existing data is then lost. You must be certain that you are selecting a disk that can legitimately be added to the disk group.

   • Optionally enter an Oracle ASM disk name for each disk. Oracle ASM provides a name if you do not.

9. Click OK to add the selected disks.

Perform the following procedures to bring a disk online or offline:

1. Access the Oracle Automatic Storage Management home page.

   See "Accessing the Oracle Automatic Storage Management Home Page" for instructions.

2. Click the Disk Groups link at the top of the page to view the Disk Groups page.

   Click the name of a disk in the Name column and Oracle Enterprise Manager displays the General page for the disk group to modify.

3. To bring a disk online, select the disk to bring online and click Online. If you bring a disk online, then Oracle ASM performs the following:

   • Oracle ASM performs the online operation on the selected disks. You can select one or more or disks, or all of the disks to bring online. If you select all of the disks, then Oracle uses the ALL keyword for this operation. Otherwise, only the selected disks are affected by the online operation.

   • During the online process, Oracle Enterprise Manager first places a disk into online mode to accommodate write operations. Then Oracle Enterprise Manager resynchronizes stale data on the disk with the current data until the disk is fully online for read operations; this is the Oracle ASM fast mirror resync feature.

   • You can also choose the By Failure Group view to perform this operation on a selected disk group. In this case, Oracle uses the SQL for disks in failure group.

   • You can also select a disk that is online, but Oracle Enterprise Manager ignores that selection and only brings disks online that were previously offline.

   • Click Yes on the Oracle Enterprise Manager Confirmation dialog to begin bringing the disk online or click No to cancel the operation. You can also click Show SQL to review the SQL that Oracle Enterprise Manager uses for the online operation.

4. To take a disk offline, select the disk to take offline and click Offline. If you bring a disk offline, then Oracle ASM performs the following:

   • Depending on how much data is stale, the operation may require additional time to complete. You can monitor the operation's progress using the Pending Operations link from the Disk Group home page.

   • The value that you set for Rebalance Power using ASM_POWER_LIMIT must be a whole number. The text on the page describes how the value of Rebalance Power affects the fast mirror resync operation. If the ASM_POWER_LIMIT is set to 0, then Oracle ASM does not perform automatic rebalance. For information about rebalance power settings and the ASM_POWER_LIMIT initialization parameter, refer to "ASM_POWER_LIMIT".

   • By default, the Rebalance Power value uses the value of the ASM_POWER_LIMIT initialization parameter.

   • Oracle Enterprise Manager displays an Offline Confirmation page and the text on this page explains that after Oracle Enterprise Manager takes the selected disks offline, the Oracle ASM instance waits for the time interval that is specified by the value that you have set for the DISK_REPAIR_TIME initialization parameter before Oracle ASM drops the disks. During the disk repair time period, you can repair the disks and then place them back online. For each disk that you successfully place online, the pending drop operation is canceled and a resynchronization operation begins.

   • If you have set DISK_REPAIR_TIME to a large value, for example, greater than one day, then this increases the possibility of data loss. This is because the files in the disk group are protected with a lower degree of redundancy during this period.

     Click Yes on the Oracle Enterprise Manager Conformation dialog to begin the offline processing or click No to stop the operation. You can also click Show SQL to see the SQL that Oracle Enterprise Manager uses for the offline operation.

You can drop disks from disk groups with Oracle Enterprise Manager.

When you drop a disk from a disk group, Oracle ASM rebalances the disk group by moving all of the file extents from the dropped disk to other disks in the disk group. Oracle ASM then releases the disk and you can then add the disk to another disk group or use it for other purposes. You can drop one or more disks in a single operation. You can also optionally set rebalance power for the drop operation. The following is a list of possible reasons for dropping a disk:

• A disk is starting to fail and you must replace it

• To upgrade a disk

• To reallocate the disk to a different disk group or reallocate the disk to a different storage system

To drop one or more disks from a disk group:

1. Access the Oracle Automatic Storage Management home page.

2. Click the Disk Groups link to display the Disk Groups property page.

3. If the Oracle Automatic Storage Management Login page appears, log in as the SYS user, connecting as SYSASM. Provide the SYS password for the Oracle ASM instance. This password was set up when the Oracle ASM instance was created.

4. Click a link in the Name column to select the disk group that contains the disks to be dropped.

   The Disk Group page appears.

5. Under the Member Disks heading, in the Select column, select the boxes for the disks that you plan to drop, and then click Remove.

   A confirmation page appears.

6. To change the rebalance power, or to set the FORCE option for dropping disks, do the following:

   1. Click Show Advanced Options.

   2. Optionally select the Force option or select a rebalance power in the Rebalance Power list.

   Note:

   You might need the FORCE option if Oracle ASM cannot read from or write to the disk.

7. Click Yes to drop the disks.

   The Disk Group page returns, and displays a state of DROPPING for each disk being dropped.

8. Refresh the page until the dropped disks no longer appear in the disk group.

When you drop a disk group, you delete the disk group optionally with all of its files. You cannot drop a disk group if any of its database files are open. Oracle ASM deletes all of the disk group contents only if you specify the including contents option. After dropping a disk group, you can add its member disks to other disk groups or use them for other purposes.

One reason to drop a disk group is to change the redundancy level (normal, high, or external). Because you cannot change the redundancy of a disk group, you must drop the disk group and then re-create it with the proper redundancy. In this case, you must back up or move disk group data before you drop the disk group.

To drop a disk group:

1. Access the Oracle ASM home page.

   See "Accessing the Oracle Automatic Storage Management Home Page" for instructions.

2. Click the Disk Group tab to display the Disk Groups page.

3. If the Oracle ASM Login page appears, log in as the SYS user, connecting as SYSASM. Provide the SYS password for the Oracle ASM instance. This password was set up when the Oracle ASM instance was created.

4. Click the box in the Select column to select a disk group that you plan to drop.

5. Click Delete and the confirmation page appears.

6. To delete the disk group even if it still contains files, click Show Advanced Options and ensure that the Including Contents option is selected. If the disk group contains files and the Including Contents option is not selected, then you cannot drop the disk group.

7. To delete a disk group that belongs to a disk group that you cannot mount, use the FORCE option in the Advanced Options confirmation dialog. The FORCE option applies to the DISMOUNTED disk group only. This option enables you to delete a disk header and mark it as FORMER.

   Caution:

   Use extreme care when using the FORCE option because the Oracle ASM instance does not verify whether the disk group is used by any other Oracle ASM instance before Oracle ASM deletes the disk group.

8. On the confirmation page, click Yes.

   For more information about dropping disks, see "Dropping Disk Groups".

Perform the following procedures to monitor disk group usage:

To view Oracle ASM disk group usage and free space:

1. Access the Oracle Automatic Storage Management home page.

   See "Accessing the Oracle Automatic Storage Management Home Page" for instructions.

2. Click the Disk Groups link to view the Disk Groups property page.

3. If the Oracle ASM Login page appears, then log in as the SYS user, connecting as SYSASM. Provide the SYS password that was set up for Oracle ASM when the Oracle ASM instance was created.

The Disk Group list page displays all of the disk groups and their space usage information.

The Usable Free column displays the space in megabytes that is available in the disk group. The values in this column consider the redundancy level of the disk group, and exclude the space that the disk group reserves for restoring full redundancy for all files in the disk group after a disk failure.

For more information, see "Managing Capacity in Disk Groups" and "Views Containing Oracle ASM Disk Group Information"

Use the FORCE option to mount a disk group when there are missing disks or missing failure groups. The FORCE option corrects configuration errors, such as incorrect values for ASM_DISKSTRING, without incurring unnecessary rebalance operations. Disk groups mounted with the FORCE option have one or more disks offline if the disks were not available at the time of the mount. You must take corrective action to restore those devices before the time set with the DISK_REPAIR_TIME value expires. Failing to restore and put those disks back online within the disk repair time frame results in Oracle ASM automatically removing the disks from the disk group. This would then require a rebalance operation to restore redundancy for all of the files in the disk group. Perform the following procedures to mount a disk with the FORCE option:

1. From the Oracle ASM home page click the Disk Groups tab.

2. Select the disk group that has a disk that you must repair and click Dismount. Click OK on the Dismount confirmation dialog. The State column of the Disk Group home page should show the Status as DISMOUNTED.

3. Perform any needed repairs to the disk in the disk group.

4. Click the box in the Select column next to the disk that you plan to force mount, then click Mount.

5. On the Disk Mount Confirmation dialog, click the Show Advanced Options link.

6. On the Mount Force Confirmation dialog, select the Force option and click Yes. You can also click No to cancel the mount force operation and Show SQL to review the SQL that Oracle Enterprise Manager uses to perform the mount force operation.

This section explains how to administer advanced disk group properties.

Perform the following steps to change the values for disk group attributes that can be altered after the disk group has been created.

1. On the Automatic Storage Disk Group List page, click a disk group name and Oracle Enterprise Manager displays the Disk Group home page.

2. Click Edit under the Advanced Attributes section.

The topics contained in this section are:

• Configuring Disk Group Compatibility Attributes

• Configuring Disk Repair Time

• Configuring Smart Scan Compatibility

• Configuring File Access Control

1. Access the Oracle Automatic Storage Management home page.

   See "Accessing the Oracle Automatic Storage Management Home Page" for instructions.

2. Click the Disk Group tab. The Disk Group page displays.
3. Select a Disk Group. The Disk Group page appears which shows all Member Disks that belong to the disk group.
4. Select an offline disk to replace. The Replace Disks page is displayed.

   Select a new disk of size equal to or greater than the original disk being replaced to ensure the same level of data protection.

5. Select a new disk and then specify the options, such as Rebalance Power, and then click OK. The disk is then replaced. Rebalance operations redistribute data evenly across all drives. Oracle ASM automatically rebalances a disk group whenever disks are added or dropped. To manually rebalance all disk groups, you must specify the Rebalance Power. Higher values use more I/O bandwidth and complete rebalance more quickly. Lower values cause rebalance to take longer, but use less I/O bandwidth. Values range from 0 to 1024.

1. Access the Oracle Automatic Storage Management home page.

   See "Accessing the Oracle Automatic Storage Management Home Page" for instructions.

2. Click the Disk Groups tab. The Disk Group page displays.
3. Click Create. In the Disk Resync Attributes section of the Create Disk Group page, you can select the value Recovery, Data or System from the Content Type drop-down list. The attribute can be set only if the ASM compatibility is greater than or equal to 12.1.0.0.
4. To edit the content type for an existing disk group, navigate to the Disk Group home page by clicking the disk group in the Disk Groups table. The Disk Group home page displays.
5. Click Edit in the Advanced Attribute Section. The Edit Advanced Attributes for Disk Group page appears. In the Disk Resync Attributes section, select from the values Recovery, Data, or System from the Content Type drop-down list.

1. Access the Oracle Automatic Storage Management home page.

   See "Accessing the Oracle Automatic Storage Management Home Page" for instructions.

2. Click the Disk Groups tab. The Disk Groups page displays.
3. Click Create. Specify the repair time for the Failure Group in the Candidate Member Disks table.
4. To edit an existing Failure Group repair time, from the Disk Group page choose the Disk Group for the repair time you want to modify. The Disk Group page appears.
5. In the Advanced Attributes section, click Edit. The Edit Advanced Attributes for Disk Group page displays.
6. In the Disk Resync Attributes section, modify the Failure Group Repair Time, then click OK. The failure Group Repair Time applies to all the failure groups in the disk group except those containing only one disk. This value overrides the disk repair time and is overridden by the actual value provided when a disk is taken offline.

1. Access the Oracle Automatic Storage Management home page.

   See "Accessing the Oracle Automatic Storage Management Home Page" for instructions.

2. Click the Disk Group tab. The Disk Group page displays.
3. Select multiple disk groups then click Rebalance. The Rebalance Disk Groups Confirmation page appears where you can set the Rebalance Power by displaying Advanced Options.
4. Set the Rebalance Power value, then click OK. The command to rebalance is submitted.

1. Access the Oracle Automatic Storage Management home page.

   See "Accessing the Oracle Automatic Storage Management Home Page" for instructions.

2. Click the Disk Group tab. The Disk Groups page displays.
3. Click a Disk Group link. The Disk Group home page General section displays the number of Pending Operations as a link to the Pending Operations page.
4. Click the link. Information on the rebalance process, along with details on the number of participating instances, are displayed.

1. Access the Oracle Automatic Storage Management home page.

   See "Accessing the Oracle Automatic Storage Management Home Page" for instructions.

2. Click the Disk Groups tab. The Disk Groups page is displayed.
3. Click the Disk Group that contains the Thin Provisioned attribute you want to change. The Disk Group page displays.
4. In the Advance Attributes section, click Edit. The Edit Advanced Attributes for Disk Group page displays.
5. In the Thin Provisioning section, select True or False from the Thin Provisioned field drop-down list. If thin provisioning is enabled, the disk space not in use can be returned to the array. This attribute can be set only if the ASM compatibility is greater than or equal to 12.1.0.0.

1. Access the Oracle Automatic Storage Management home page.

   See "Accessing the Oracle Automatic Storage Management Home Page" for instructions.

2. Click the Disk Group tab. The Disk Group page is displayed.
3. Click Scrub. The Scrub Disk Group page is displayed where you can use advanced options such as repair, power level, wait and force. You can also use the scrub action on disks and files.
4. Provide the advance option and click OK. A background process is initiated that scrubs the disk group.

1. Access the Oracle Automatic Storage Management home page.

   See "Accessing the Oracle Automatic Storage Management Home Page" for instructions.

2. Click the Disk Group tab. The Disk Group page displays.
3. Click a Disk Group link. The Disk Group General Section displays a Pending Operation link if a scrubbing process is ongoing.
4. Click the link. Details on the scrubbing process are displayed.

1. From Targets menu, select All Targets.
2. On the All Targets page, select any target of type Automatic Storage Management.
3. On the target home page, from Automatic Storage Management menu, select Configuration Parameters.
4. On the Configuration page, click Manage Disk Provisioning. The ASM Filter Driver Page is displayed.
5. On the Disks available for Provisioning table, click Discover to discover additional Oracle ASM disks.
6. In the Discover Disks dialog box, enter additional discovery paths from where you would like to provision disks. If you are providing more than one path, then ensure that the values are separated by a comma.

   For example, '/dev/','/tmp'.

7. Click Ok.

1. From Targets menu, select All Targets.
2. On the All Targets page, select any target of type Automatic Storage Management.
3. On the target home page, from Automatic Storage Management menu, select Configuration Parameters.
4. On the Configuration page, click Manage Disk Provisioning. The ASM Filter Driver Page is displayed.
5. From the Disks available for Provisioning table, select one or more disks, then click Provision.
6. The Provision Disks dialog box lists all the disks that were selected for provisioning. You can update the Label info if you want, then click OK.

1. From Targets menu, select All Targets.
2. On the All Targets page, select any target of type Automatic Storage Management.
3. On the target home page, from Automatic Storage Management menu, select Configuration Parameters.
4. On the Configuration page, click Manage Disk Provisioning. The ASM Filter Driver Page is displayed.
5. From the Provisioned Disks table, select one or more disks, then click Release.
6. In the Release Provisioned Disks dialog box, click Yes to release the disks

You can monitor Oracle ASM performance with the Oracle Enterprise Manager Performance page.

To monitor Oracle ASM performance:

1. Access the Oracle Automatic Storage Management home page.

   See "Accessing the Oracle Automatic Storage Management Home Page" for instructions.

2. Click the Performance link to view the Performance property page.

3. Determine the view and refresh rate of the performance graphs with the View and Refresh options. Click Refresh to manually refresh the graphs. The refresh option has the following two intervals:

   • Manual refresh: manual, 15 second interval, 30 second interval

   • Historical data: Last 24 hours, last 7 days, last 31 days

   For more information, refer to "Performance and Scalability Considerations for Disk Groups".

When you check the integrity of Oracle ASM disk groups, Oracle Enterprise Manager performs consistency checks on all of the disk group metadata. If Oracle ASM detects errors, then Oracle ASM stores information about errors in the alert log. To check disk groups, perform the following steps:

1. From the Disk Groups page, select a disk group in the list and click Check.

   A confirmation dialog for the check disk group operation displays.

2. Select Check Without Repair to record information about disk group inconsistencies in the alert log. In this operation, Oracle ASM does not resolve the errors. Select Check And Repair to attempt to repair errors that Oracle Enterprise Manager identifies during the disk group consistency check.

3. Click Yes to start the disk group check operation or No to cancel it. You can also select Show SQL to review the SQL statements that the disk group check operation uses. Click OK to run the check operation as a command. To schedule a job, click Schedule Job. Optionally, you can modify or reenter the job name and description. Also provide host credentials and enter the scheduling options by selecting Immediately or Later and modifying the date and time as needed. Click OK to schedule the job or Cancel to terminate the job creation process.