Storage Classes
Use this page to define, modify, copy, or delete a storage class that is used by the IBM® TS7700 to automate storage management through classification of data sets and objects.
The Storage Classes table displays defined storage classes available to
control data sets and objects within a cluster. While storage classes are visible from all TS7700
Clusters, only those clusters attached to a cloud or physical library can alter Tape Volume Cache
Preferences. TS7700 Clusters that do not possess a cloud or physical library do not remove physical
volumes from the tape cache, so the Tape Volume Cache Preference for these clusters is always
Preference Level 1. This also applies when copying an existing storage class from a
cluster that is attached to a physical library to another cluster in the grid that does not possess
a physical library.
Restriction: If the accessing
cluster is a TS7720D all
data is pinned in cache. Volumes cannot be removed from cache and removal preference options are not
available. The Storage Classes table is automatically populated with a
default storage class, which cannot be modified. No additional storage classes can be created and no
actions are available from the Storage Classes table.
You can use the Actions menu on the Storage Classes
table to:
- Create a new storage class
- Modify an existing storage class
- Copy an existing storage class
- Copy an existing storage class from the accessing cluster to another cluster in the grid
- Delete one or more storage classes
Status information that is displayed in the Storage Classes table
includes:
- Name
- The name of the storage class. The value in this field must be in the range 1 - 8 characters in
length. Each storage class within a cluster or cluster pair must
have a unique name. Valid characters for this field are:
A-Z, 0-9, $, @,and #
The first character of this field cannot be a number. This is the only field that cannot be modified once added.
- 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.
- 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.
Use the pull-down menu on the Storage Classes table to add a storage class or modify, copy, or delete an existing storage class.