Managing Scratch Cartridges

Scratch cartridges either contain no data or data that can be overwritten. A user or application mounts a scratch cartridge to write new data on that cartridge.

To assign scratch status:

Cartridges can be defined as scratch cartridges and assigned to scratch pools by the set scratch command.
The watch_vols utility can automatically assign cartridges to a scratch pool based on the cartridges' vol_id or volrange. See "watch_vols".

Clearing a volume scratch status:

A cartridge's scratch status is cleared when the cartridge is successfully mounted (either by a mount scratch or a normal mount request).

Note:
The set scratch command can be used to clear scratch status.Although a volume's scratch status is cleared when a volume is mounted, the pool id is not cleared. The result is a data volume assigned to the pool.

The set scratch command can also be used to assign a data volume to a scratch pool using:

set scratch off pool_id vol_id | volrange

You must ensure that the library has enough available scratch cartridges to satisfy scratch mount requests. For more information see:

The following sections provide additional information about managing scratch cartridges and scratch pools:

Displaying Scratch Pool and Scratch Cartridge Information

To display scratch pool information, use the following ACSLS functions:

query pool

Displays scratch pool attributes. See query pool
query scratch

Displays scratch cartridge information. See query scratch
query mount *

Displays the status of media-compatible cartridges for a specified scratch pool (and, optionally, for a specific cartridge media type within the pool). See query mount *
Customized volume report

Reports selected scratch volume information. See Creating a Logging Volume Statistics Report

Adding Scratch Cartridges to the Library

Use this procedure to add scratch cartridges to the library.

To add scratch cartridges to the library:

If necessary, create a new scratch pool:

For more information, see query scratch.
Enter scratch cartridges into the library.

For more information, see Entering Cartridges.
Define the cartridges you entered in Step 2 as scratch cartridges and assign them to a scratch pool.

This can either be done using policies defined in vol_attr.dat for the watch_vols utility or using set scratch.

Rebalancing Scratch Pools

Use this procedure to rebalance scratch pools by moving scratch cartridges from one pool to another.

To rebalance scratch pools:

Display the attributes of all scratch pools:
```
query pool all
```
For more information see query pool.
Use the query scratch command to display the IDs of scratch cartridges in pools you want to rebalance.

For more information, see query scratch.
Use the set scratch command to move scratch cartridges from one pool to another.
For example, to reassign cartridges YUMA20 through YUMA80 (which currently reside in pool 5 to pool 10, enter:
```
set scratch 10 YUMA20-YUMA80
```
For more information, see set scratch.

Deleting Scratch Pools

To manage scratch pools, you may want to delete any scratch pools that no longer contain scratch cartridges. You cannot delete the common pool (Pool 0). Notice that you can delete only empty scratch pools; you cannot delete a scratch pool if it contains either data or scratch cartridges. You can, however, use Deleting All Empty Pools to delete all empty pools (ACSLS will not delete any pools that contain scratch or data cartridges).

Emptying a Scratch Pool

Use this procedure to empty a scratch pool before deleting it.

To empty a scratch pool:

To move data cartridges out of the pool, enter:
set scratch off 0 vol_id volrange ...

Where the vol_id or volrange specifies the data cartridges you want to move to the common pool (pool 0). For more information, see set scratch.
To move scratch cartridges out of the pool, do one of the following:
- Move the cartridges to another pool.
- See Ejecting Cartridges. If you eject scratch cartridges, however, ACSLS no longer manages these cartridges. If you later want to use these cartridges, you must reenter them and assign them to a scratch pool.

Deleting a Single Pool

To delete a single pool:

delete pool pool_id

Deleting All Empty Pools

The delete pool all command deletes only empty scratch pools, not pools that contain scratch or data cartridges.

To delete all empty pools:

delete pool all

Mounting Scratch Cartridges

The mount scratch (mount * using cmd_proc) command selects a scratch cartridge that is compatible with, and as close as possible to, the specified drive and mounts it in the drive. If a pool is specified, the scratch cartridge must be assigned to that pool.

If the mount of the scratch cartridge fails because the scratch cartridge is not found in its home cell or another recoverable error, ACSLS automatically tries to select another scratch cartridge and retry the mount.

You can set a Volume Access Control policy for whenever a scratch cartridge is mounted, it is automatically owned by the ACSAPI user who mounted it. See Establishing Ownership of Your Volumes.

Use the following procedures to mount scratch cartridges in single-media and mixed-media environments.

Single-Media Environments

To mount a cartridge from a specified pool:
```
mount * drive_id pool_id
```
If no cartridge is available from the specified pool and the pool has been set for “overflow," ACSLS selects a cartridge from the common pool (pool 0).
To mount a cartridge from the common pool:
```
mount * drive_id
```

Mixed-Media Environments

To mount a scratch cartridge with a specified media type from a specified pool:
```
mount * drive_id pool_id media media_type
```
If no cartridge is available from the specified pool and the pool has been set for overflow ACSLS will select a cartridge with the specified media type from the common pool (pool 0).
To mount a scratch cartridge from a specified pool with a media type determined by scratch preferences:
```
mount * drive_id pool_id media *
```
If no cartridge is available from the specified pool and the pool has been set for overflow ACSLS will select a cartridge from the common pool (pool 0) according to the defined scratch preferences.
To mount a cartridge from the common pool with a specified media type:
```
mount * drive_id media media_type
```
To mount a cartridge from the common pool with a media type determined by scratch preferences:
```
mount * drive_id media *
```

Unscratching Cartridges

Scratch cartridges are automatically reassigned to data cartridge status when they are mounted.

Use this procedure to “unscratch" cartridges (return them to data cartridge status) that were scratched in error.

To unscratch cartridges:

Use the query pool and query scratch commands to display the cartridge and pool IDs of the cartridges to unscratch.

For more information see query pool and query scratch.
To unscratch the selected cartridges, enter:
```
set scratch off 0 vol_id volrange.
```
Where the vol_idor volrange specifies the cartridges you want to change from scratch mode and move them to the common pool (pool 0). For more information, see set scratch.