Array data section

Bit(s)

Description

0

Reserved (set to B'0')

1-3

Logical Volume Migration Algorithm

Value

Description

0

Least Recently Used (LRU) Managed. The logical volumes in this preference level are removed from the cache based on a least recently used algorithm.

1

Largest Size Managed. The logical volumes in this preference level are removed from the cache based on their size with the largest volumes being removed first.

2-7

Reserved

4-31

Reserved (set to B'0')

This four byte field contains a count, that is a snapshot taken when statistics are calculated at the end of the hour, of the number of volume assigned to the preference level that are still cache resident. For volumes that are currently mounted and do not have a preference level established (that is done when a volume is unloaded), they are credited to the count for preference level 1.

This four byte field contains a count, that is a snapshot taken when statistics are calculated at the end of the hour, of the amount of cache space used by the volumes assigned to the preference level that are still cache resident. For volumes that are currently mounted and do not have a preference level established (that is done when a volume is unloaded), their size is credited to the count for preference level 1. The cache space is accumulated in bytes and reported in an integral multiple of 1,048,576 bytes (1 MByte).

This four byte field contains a rolling average cache age, in minutes, of the logical volumes that were assigned to the preference level when the volume was migrated from the cache. The rolling average is calculated based on the cache age of the volumes that have been migrated from the cache over the last 4 hours. Cache age is measured from when a volume is first closed after being created or recalled into cache until it has been migrated from cache. Each volume's cache age is rounded up to the nearest minute. The value is calculated at the end of the hour.

This four byte field contains a rolling average cache age, in minutes, of the logical volumes that were assigned to the preference level when the volume was migrated from the cache. The rolling average is calculated based on the cache age of the volumes that have been migrated from the cache over the last 48 hours. Cache age is measured from when a volume is first closed after being created or recalled into cache until it has been migrated from cache. Each volume's cache age is rounded up to the nearest minute. The value is calculated at the end of the hour.

This four byte field contains a rolling average cache age, in minutes, of the logical volumes that were assigned to the preference level when the volume was migrated from the cache. The rolling average is calculated based on the cache age of the volumes that have been migrated from the cache over the last 35 days. Cache age is measured from when a volume is first closed after being created or recalled into cache until it has been migrated from cache. Each volume's cache age is rounded up to the nearest minute. The value is calculated at the end of the hour.

This two byte field contains the average time, in seconds, that the Virtual Tape Server subsystem took to complete the execution of a fast-ready mount request for a virtual device. Mount time is accrued from the time the mount request is accepted until the mount is completed. The mount time is accredited to the hour it was completed.

This two byte field contains the number of mount requests completed using the Fast-Ready facility by the Virtual Tape Server subsystem in the last hour. The Fast-Ready facility is used for PLF Library Mount orders where a category is specified and the specified category has the Fast-Ready attribute set or a VOLSER is specified and that VOLSER, at the time the mount request was received, is assigned to a category that has the Fast-Ready attribute set.

This two byte field contains the average time, in seconds, that the Virtual Tape Server subsystem took to complete the execution of a mount request for a virtual device where the requested volume was in the Tape Volume Cache. Mount time is accrued from the time the mount request is accepted until the mount is completed. The mount time is accredited to the hour it was completed.

This two byte field contains the number of mount requests that were completed by the Virtual Tape Server subsystem in the last hour because the required volume was resident in the Tape Volume Cache.

This two byte field contains the average time, in seconds, that the Virtual Tape Server subsystem took to complete the execution of a mount request for a virtual device where the requested volume had to be recalled from a stacked volume. Mount time is accrued from the time the mount request is accepted until the volume has been recalled and the mount completed. The mount time is accredited to the hour it was completed.

This two byte field contains the number of mount requests that were completed by the Virtual Tape Server subsystem in the last hour that required a logical volume to be recalled from a stacked volume back into the Tape Volume Cache.