# VTS TS7700-series Cache Preference Group

This attribute group provides basic information about a cache preference group in a TS7700 tape virtualization system. All attributes are derived from the HSM HSM - Cache - Partition - Preference Group Container record of the "Hnode HSM Historical Record."

35 Day Average Cache Age: 35-day rolling average of cache age, in minutes, of the virtual volumes migrated out of the cache partition that were assigned to the preference group this data is for. Cache age is measured from when a volume is created or recalled into cache until it has been migrated from cache. The cache age of each volume is rounded up to the nearest minute. This data is calculated once an hour, on the hour. The data for this field is calculated at the end of the interval.

4 Hour Average Cache Age: Four-hour rolling average of cache age, in minutes, of the virtual volumes migrated out of the cache partition that were assigned to the preference group this data is for. Cache age is measured from when a volume is created or recalled into cache until it has been migrated from cache. The cache age of each volume is rounded up to the nearest minute. This data is calculated once an hour, on the hour. The data for this field is calculated at the end of the interval.

48 Hour Average Cache Age: 48-hour rolling average of cache age, in minutes, of the virtual volumes migrated out of the cache partition that were assigned to the preference group this data is for. Cache age is measured from when a volume is created or recalled into cache until it has been migrated from cache. The cache age of each volume is rounded up to the nearest minute. This data is calculated once an hour, on the hour. The data for this field is calculated at the end of the interval.

Cluster ID: Hexadecimal value indicating the cluster ID. Values are 0 to 7.

Data Resident in Cache: Amount of data in the TVC partition whose volumes are assigned to the preference this data is for. The value is reported in increments of 1 MB. Any residual data causes the value to be rounded up to the next higher value. This metric is the value at the end of the interval.

Grid Library Sequence Number: Library Sequence Number of the Grid (Composite) library.

Machine Model: Machine model of the node. Initially this field is set to "V06".

Machine Serial Number: Serial number of the node. This field is left justified and padded with blanks. The format is XX-YYYYY where XX is the plant of manufacture and the YYYYY is the sequence number of the node's machine. The dash character (-) is fixed. It should be noted that there can only be one machine per-cluster.

Machine Type: Machine type of the node. Initially this field is set to "3957".

Managed System: The SMS name of this system.

Node ID: A hexidecimal field that indicates the ID of the node.

Partition Container Number: Integer value 0-7 that indicates which cache partition you are viewing.

Preference Group Number: Integer value (0 or 1) that denotes the preference group of this particular row.

Timestamp: Time table row was created in CT timestamp format.

VE Code Level: Code level of the TS7700 Virtualization Engine™ (VE). The VE code level is expressed as `Version.Release.Modification.Fix` in a decimal form.

Virtual Volumes in Cache: Number of virtual volumes in the Tape Volume Cache (TVC) partition that are assigned to the preference group this data is for. This is the value at the end of the interval.

Volumes Migrated Last 35 Days: Number of virtual volumes migrated from the cache partition over the past 35 days that are assigned to the preference group this data is for. This data is calculated once an hour, on the hour. The data for this field is calculated at the end of the interval.

Volumes Migrated Last 4 Hours: Number of virtual volumes migrated from the cache partition over the past 4 hours that are assigned to the preference group this data is for. This data is calculated once an hour, on the hour. The data for this field is calculated at the end of the interval.

Volumes Migrated Last 48 Hours: Number of virtual volumes migrated from the cache partition over the past 48 hours that are assigned to the preference group this data is for. This data is calculated once an hour, on the hour. The data for this field is calculated at the end of the interval.