Modify storage class

Use this page to modify a storage class construct used in the IBM® TS7700 Grid.

To modify a storage class:

From the Storage Classes page, navigate to the Storage Classes table.
Select the storage class to be modified.
Select Modify... from the Actions menu.
Change any of the following values on the Modify Storage Class panel. You cannot modify a storage class name.
Note: Storage class options displayed depend on the accessing cluster's configuration.

Restriction: If the accessing cluster is a TS7720D you cannot modify storage classes.

Description

An optional description of the storage class. The value in this field must be 0 - 70 characters in length.

Partition

The name of the partition associated with the Storage Class. A partition must be active before it can be selected as a value for this field. This field is only displayed if the cluster is a TS7700 attached to a physical library.

Notes:

A DS8000 object partition cannot be selected.
A dash (-) indicates that the Storage Class contains a partition that was deleted. Any volumes that are assigned to go to the deleted partition are redirected to the primary partition.

Tape Volume Cache Preference

The preference level for the storage class; it determines how soon volumes are removed from cache following their copy to tape. This field is visible only if the TS7700 Cluster attaches to a physical library. If the selected cluster does not possess a physical library, volumes in that cluster's cache display a Level 1 preference. Possible values are:

Use IART: Volumes are removed according to the Initial Access Response Time (IART) of the TS7700.
Level 0: Volumes are removed from the tape volume cache as soon as they are copied to tape
Level 1: Copied volumes remain in the tape volume cache until more space is required, then are the first volumes that are removed to free space in the cache. This is the default preference level that is assigned to new preference groups.

Premigration Delay Time

The number of hours until premigration can begin for volumes in the storage class, based on the volume time stamp designated by Premigration Delay Reference. Possible values range 0 - 65535. If 0 is selected, premigration delay is disabled. This field is visible only for TS7700 Clusters that are attached to a physical library.

Premigration Delay Reference

The volume operation that establishes the time stamp from which Premigration Delay Time is calculated.This field is visible only for TS7700 Clusters that are attached to a physical library. Possible values include:

Volume Creation: The time at which the volume was created by a scratch mount or write operation from beginning of tape.
Volume Last Accessed: The time at which the volume was last accessed.

Volume Copy Retention Group

The name of the group that defines the preferred auto removal policy applicable to the logical volume.

The Volume Copy Retention Group provides additional options to remove data from a disk-only TS7700 as the active data reaches full capacity. Volumes become candidates for removal if an appropriate number of copies exist on peer clusters AND the volume copy retention time has elapsed since the volume was last accessed. Volumes in each group are removed in order based on their least recently used access times. The volume copy retention time describes the number of hours a volume remains in cache before becoming a candidate for removal.

This field is displayed only if the cluster is a disk-only cluster or part of a hybrid grid (one that combines TS7700 Clusters that both do and do not attach to a physical library). If the logical volume is in a fast ready category and resides on a disk-only cluster, removal settings no longer apply to the volume and the volume is a candidate for removal. In this instance, the value displayed for the Volume Copy Retention Group is accompanied by a warning icon.

Prefer Remove: Removal candidates in this group are removed prior to removal candidates in the Prefer Keep group.
Prefer Keep: Removal candidates in this group are removed after removal candidates in the Prefer Remove group.
Pinned: Copies of volumes in this group are never removed from the accessing cluster. The volume copy retention time does not apply to volumes in this group. Volumes in this group that are subsequently moved to scratch become priority candidates for removal.
CAUTION:
Care must be taken when assigning volumes to this group to avoid cache overruns.

Volume Copy Retention Time

The minimum amount of time (in hours) after the copy reference configuration (last accessed or at volume creation) that the copy can be removed from cache. The copy is said to be expired after this time has passed, and the copy then becomes a candidate for removal. Possible values include any in the range 0 - 65536; the default is 0.

Note: Field is only visible if the selected cluster is a TS7700 and all the clusters in the grid operate at microcode level 8.7.0.xx or later.

If the Volume Copy Retention Group displays a value of Pinned, this field is disabled.

Volume Copy Retention Reference

The volume operation that establishes the time stamp from which Volume Copy Retention Time is calculated. Possible values include:

Volume Creation: The time at which the volume was created by a scratch mount or write operation from beginning of tape.
Volume Last Accessed: The time at which the volume was last accessed.

If the Volume Copy Retention Group displays a value of Pinned, this field is disabled.

To complete the operation click OK. To abandon the operation and return to the Storage Classes page, click Cancel.