You use ALTER STOGROUP to modify the definition of a storage group.
Please note, however, that the definition of a storage group cannot be modified if the storage group is entered in the media table.
The STOGROUPS view of the INFORMATION_SCHEMA provides you with information on which storage groups have been defined (see chapter "Information schemas").
The current authorization identifier must have the special privilege CREATE STOGROUP and must own the storage group.
ALTER STOGROUP stogroup { ADD VOLUMES ( volume_name ,...) [ON dev_type ] |
DROP VOLUMES ( volume_name ,...) |
PUBLIC |
TO catid }
stogroup
Name of the storage group for which the definition is to be updated. You can qualify the name of the storage group with a database name.
ADD VOLUMES (volume_name,...)
Adds new private volumes to the storage group. volume_name is an alphanumeric literal indicating the VSN of the volumes. Each VSN can only be specified once for a storage group.
If the storage group previously consisted of private volumes, the new volumes being added must have the same device type.
A storage group can comprise up to 100 volumes.
ON dev_type
Alphanumeric literal indicating the device type of the private volumes.
You must specify the device type if the storage group was previously set up on public volumes (PUBLIC).
If the storage group previously consisted of private volumes, you can omit ON dev_type. If you do specify ON dev_type, you must specify the same device as before.
ON dev_type omitted:
The storage group consists of private volumes which all have the same device type as before.
DROP VOLUMES ( volume_name,...)
Deletes individual private volumes from the definition of the storage group. volume_name is an alphanumeric literal indicating the VSN of the volume.
You cannot delete the last volume in a storage group.
PUBLIC
The storage group is set to the default pubset of the BS2000 user ID under which the DBH is running. All private volumes are deleted from the definition of the storage group.
TO catid
The new catalog identifier for the volumes is entered in the definition of the storage group. catid is an alphanumeric literal indicating the new catalog ID.
In the case of private volumes, the new catalog ID is only used for catalogging the files. The files themselves are still stored on the private volumes. In the case of a pubset, the catalog ID of the pubset on which the storage group is located is changed.
Effect of ALTER STOGROUP
The ALTER STOGROUP statement only modifies the definition of the storage group. It does not affect existing spaces that the volumes in the storage group use.
Volumes deleted from the storage group are not, however, used for new storage space assignments for the spaces. Volumes can be deleted from the storage group explicitly with DROP VOLUME or implicitly by changing from public volumes (PUBLIC) to private volumes or vice versa.
The new definition of the storage group takes effect when files (spaces or backups) are created in the storage group.
Examples
The example below changes the storage group from private volumes to the pubset with the catalog ID O. This is done in two steps.
ALTER STOGROUP stogroup4 PUBLIC
ALTER STOGROUP stogroup4 TO 'O'
The example below changes the storage group STOGROUP5 from PUBLIC to private volumes. The catalog ID for the files in the storage group remains unchanged.
ALTER STOGROUP ordercust.stogroup5
ADD VOLUMES ('DX017A','DX017B') ON 'D3435'
See also
CREATE STOGROUP