# HSM CDS

The HSM CDS attributes provide space allocation and utilization information for each of the HSM control data sets.

DDNAME: The DDNAME of this data set or cluster. Specific DDNAMEs are associated with specific HSM functions:

- DDNAMEs MIGCAT, MIGCAT2-4, BAKCAT, and BAKCAT2-4 are associated with migration.
- DDNAME OFFCAT is associated with the OCDS, which contains information about tape backup volumes and tape migration level 2 volumes.
- DDNAME Journal is associated with the HSM Journal.

The journal contains a duplicate of each record in the control data sets that has changed since the BCDS, and OCDS were last backed up.

Display Order: The order in which the data sets are displayed.

Managed System: The SMS name of this system.

Number of Extents Data Component: The number of extents in the data component of this cluster. A high number of extents can indicate a need for re-allocation or reorganization of this component. Use IDCAMS LISTCAT to review splits.

Number of Extents Index Component: The number of extents in the index component of this cluster. A high number of extents can indicate a need for re-allocation or reorganization of this component. Use IDCAMS LISTCAT to review splits.

Percent Available Space Data Component: The amount of available space in an HSM control data set, expressed as a percentage of the total available space. This value is based on the high allocated RBA and the available space in the component. You can enable aggregation for this attribute in Tivoli® Data Warehouse.

Percent Available Space Index Component: The amount of available space in an HSM control data set, expressed as a percentage of the total available space. This value is based on the high allocated RBA and the available space in the component. You can enable aggregation for this attribute in Tivoli Data Warehouse.

Percent Free Space Data Component: The amount of unused space in an HSM control data set, expressed as a percentage of the total available space. This is based on the high allocated RBA and high used RBA. You can enable aggregation for this attribute in Tivoli Data Warehouse.

Percent Free Space Index Component: The amount of unused space in an HSM control data set, expressed as a percentage of the total available space. This is based on the high allocated RBA and high used RBA. You can enable aggregation for this attribute in Tivoli Data Warehouse.

Size (KB) Data Component: The total amount of space, in units of 1024 bytes, allocated to this component. You can enable aggregation for this attribute in Tivoli Data Warehouse.

Size (KB) Index Component: The total amount of space, in units of 1024 bytes, allocated to this component. You can enable aggregation for this attribute in Tivoli Data Warehouse.