# VTS Cache

The VTS Cache attributes provide performance and capacity information about the cache for a virtual tape server (VTS).

Average Recall Throttling Value: The average of the NON-ZERO throttling values over the last hour for the VTS where recall was the predominate reason.

Average Throttling Value: The average of both the ZERO and the NON-ZERO throttling values over the last hour for the VTS.

Average TVC Volume Age Minutes: The percentage of throttling over the last hour for the VTS where write overrun was the predominate reason.

Average Write Throttling Value: The average of the NON-ZERO throttling values over the last hour for the VTS where write overrun was the predominate reason.

Cache Hits: The count of cache hits a mount requests for a virtual tape volume in AVTS for which the virtual tape volume is already located in the TVC. In this case, there is no physical tape mount associated with the virtual mount request.

Fast Ready Mounts: The count of fast ready mounts. A mount attribute that allows a scratch mount request in a virtual tape server to be satisfied by the tape header information kept in the TVC for a previously-initialized virtual tape volume.

GB TVC Cache: The size of the cache in the TVC of the VTS in units of gigabytes.

Managed System: The SMS name of this system.

Maximum TVC Volume Age Minutes: The maximum age in minutes, of all virtual tape volumes in the TVC at the end of the reporting interval.

Pre-migration Mounts: The number of processes used to copy virtual volumes to logical volumes. For example, from the TVC to a physical tape, by the VTS. Normally, this number is relatively high after high write activity.

Recall Throttling Percent: The percentage of throttling over the last hour for the VTS where recall was the predominate reason.

Stage-In Mounts: The count of stage-in mounts. A stage-in mount is a mount request for a virtual tape volume in a virtual tape system for which the virtual tape volume is not residing in the TVC. In this case, there is a physical tape mount associated with the virtual mount request to access the logical volume from a physical tape.

Time Stamp: Displays the date and time this data was collected from the VTS.

TVC Virtual Volume Count: The number of virtual volumes in the TVC at the end of the reporting interval.

TVC Virtual Volume Size MB: The average size in megabytes of the virtual volumes in the TVC at the end of the reporting interval.

VTS Library Type: Specifies the library type of this VTS. Values for library type are:

- STANDALONE VTS: a VTS that is not part of a peer-to-peer VTS environment.
- DISTRIBUTED VTS: a VTS that is part of a peer-to-peer VTS environment, but has not been designated for user interface commands.
- DISTRIBUTED USER INTERFACE VTS: a VTS that is part of a peer-to-peer VTS environment, and has been designated for user interface commands.
- COMPOSITE VTS: the logical view of a peer-to-peer VTS environment.

VTS Name: Specifies the name of this virtual tape server.

Write Throttling Percent: The percentage of 30-second intervals where there was a non-zero throttling value and write overrun was the predominate reason.