Scratch Pools - Configuration

Create Spare Media Group

Every library has a default scratch pool, which is created when the library is configured. You can create any number of additional scratch pools, and assign these to different storage policy copies that access the library. You can also designate a user-defined scratch pool as the default for the library.

The ability to create scratch pools and assign them to specific storage policy copies enables you to ensure that critical operations always have the media that they need. For example, assume that you regularly back up both a file server containing mission-critical data and a number of user PCs. You may want to prevent situations in which data secured from less important user PCS use up all available media, causing vital data protection operations on file server to fail. You can do this by creating a scratch pool specifically for the storage policy copies that conduct data protection operations on file servers. You can, if necessary, delete these non-default scratch pools.

You can move media between scratch pools. In the example above, if you noticed that the supply of media in the scratch pool dedicated to the file server was getting low, you could logically reassign media from another scratch pool to the file server pool.

You can also verify the media to confirm whether the media information displayed in the CommCell Console matches the OML in the media.

Procedure

1. From the CommCell Browser, navigate to Storage Resources > Libraries > <library>

2. Right click the Media By Groups icon for the library in which you want the scratch pool created, and then click New ScratchPool from the short-cut menu.

3. You can create new scratch pools for the following:

   Spare Media Group	Click to create a new scratch pool for spare media.
   Cleaning Media Group	Click to create a new scratch pool for cleaning media.	For more information, see Cleaning Media
   Retired Media Group	Click to create a new scratch pool for deprecated media.	For more information, see Retired Media
   Overwrite Protect Media Group	Click to create a new scratch pool for media that should not be used for any write operations.	For more information, see Overwrite Protect Media

4. In the Spare Group Propertiesdialog box, enter the name of the new scratch pool in the Name field. and choose the appropriate options and click OK.

   When you first create a scratch pool, it is empty. You must either import media into the media group, or move media from another media group .

Specify the Minimum Number of Media in a Scratch Pool

You can establish a low watermark for each scratch pool. This parameter represents the minimum number of media that should be available inside the library for the scratch pool at all times. If the number of available media in the scratch pool falls below the low watermark, the system logs a message in the Event Viewer and generates the MediaAgents (Insufficient Storage) alert, if configured. You can view the status of media available in the scratch pools by generating the Scratch Pool Report.

The low watermark for all user created scratch pools in the CommCell can be established in the Default low-water mark for newly created Scratch Pools option established in the Service Configuration tab of the Media Management Configuration dialog box in the Control Panel. If necessary, you can modify the low watermark for the individual scratch pools.

When you establish a low watermark, consider the media requirements of all operations (e.g., data protection operations, auxiliary copies, synthetic full backups) that draw from the scratch pool. The low watermark should be high enough to ensure that you will be notified of the need for more media while there are still enough media available to allow running operations to complete. For example, if the operations that access a particular scratch pool regularly fill two media every week, you might set the low watermark at three. This way, you will be alerted every week to add more media to the scratch pool while it still contains sufficient media to handle its normal operational load.

Procedure

1. From the CommCell Browser, right-click the scratch pool for which you wish to specify the minimum number, and then click Properties.

2. From the General tab use the option provided in Watermark for Spare Media in the pool area to establish a minimum number of media in the scratch pool.

3. When you are satisfied with your changes, click OK.

Move Media from One Scratch Pool to Another

1. From the CommCell Browser, select the appropriate scratch pool.

   The contents of the scratch pool appear in the right pane.

2. Right-click the media that you want to move, and then click Move.

3. In the Move Media dialog box that appears, select the appropriate scratch pool.

   If it is cleaning media, select Cleaning Media pool.

4. Click OK.

   The selected media is reassigned to the destination scratch pool.

Move Media in Bulk from One Scratch Pool to Another

1. From the CommCell Browser, right-click the appropriate scratch pool (that is, the source pool), and then click Move Media.

   The Move Media dialog box appears.

2. In No. of Media to be moved box, enter the number of media to be moved.

3. In the Destination Scratch Pool list, select the destination scratch pool.

4. Click OK.

   The selected media is reassigned to the destination scratch pool.

Delete a Scratch Pool

The following scratch pools cannot be deleted:

• A scratch pool that is associated with a storage policy copy.

• A scratch pool that has been designated as the default scratch pool for the library.

To delete a scratch pool:

1. From the CommCell Browser, right-click the scratch pool that you want to delete, and then click Delete.

2. A confirmation prompt appears, asking if you are sure that you want to delete this scratch pool. Click Yes to delete.

   The scratch pool is deleted and the CommCell Browser display is updated and all of its spares are displayed as undiscovered media.

Change the Default Scratch Pool

To change the default scratch pool:

1. From the CommCell Browser, right-click the library for which you wish to change the default scratch pool, and then click Properties.

2. Select the name of the scratch pool that you wish to designate as the default scratch pool from the Default Scratch Pool list.

3. Click OK to save the changes.

Change the Scratch Pool Associated With a Storage Policy Copy

To change the scratch pool for a storage policy copy:

1. From the right pane of the CommCell Browser, right-click the storage policy copy for which you wish to change the scratch pool, and click Properties.

2. From the General tab of the Copy Properties dialog box, select another scratch pool from the Scratch Pool list.

3. Click OK to save your changes.