The MAREN user can combine one or more tapes which are logically related to form a volume group.
He/She determines the criteria according to which the tapes are selected for the volume group. He/She assigns this volume group a name. He/She uses this name to address the tapes of the volume group as a whole in the MAREN statements.
The name of the volume group is another attribute for a tape and is stored in the MAREN catalog. All files which are located on the tape belong to the same volume group. When a volume group is defined for a file on a tape, MAREN automatically updates all the filespecific catalog entries of this tape.
Only reserved tapes can be assigned to a volume group. When the tape is released, the volume group assignment of MAREN is canceled again.
Tapes can be assigned to a volume group at different times during MAREN operation:
- Assignment when reserving a free tape using the MAREN or MARENADM statement RESERVE-FREE-VOLUME VOLUME-GROUP=
- Assignment while scratch tapes are being written
The MAREN statement ADD-MAREN-FILE-ENTRY USAGE=*SCRATCH (VOLUME-GROUP=) enables the MAREN user to assign scratch tapes to a volume group while they are being written (see "ADD-MAREN-FILE-ENTRY Adds an entry to the MAREN TFT"). The MAREN statement REMOVE-MAREN-FILE-ENTRY FILE-NAME=*ALL-SCRATCH-FILES is used to reset the entry in the MAREN TFT again for all future scratch tapes (see "REMOVE-MAREN-FILE-ENTRY Removes an entry from the MAREN TFT"). - Assignment with the MAREN or MARENADM statement MODIFY-VOLUME- ATTRIBUTES
The name of a volume group is a further attribute for a tape. Nevertheless, when the tapes are selected using the VOLUME=<vsn>(...) and VOLUME=*INTERVAL(...) operands, the FILE-SEQUENCE operand is always specified in addition. The file sequence number specifies the file whose catalog entry is to be modified. The default value is 1. When assigning volume groups, MAREN takes the file sequence number into account as a selection criterion. However, to ensure file consistency, all of this tape’s archive entries are modified, i.e. all the files located on the tape then belong to the defined volume group.
The following MAREN or MARENADM statements enable the MAREN user to select tapes by means of the volume group and then to process them further:
| MAREN or MARENADM statement | Meaning |
| EXPORT-VOLUME | The VOLUME-GROUP= operand defines the volume group to which a tape must belong to permit it to be exported. |
MODIFY-VOLUME-ATTRIBUTES | The VOLUME-GROUP= operand defines the volume group to which a tape must belong to permit it to be processed. |
| PRINT-VOLUME-ATTRIBUTES | One field is provided for the volume group in each of the input masks for the selection, sort and layout parameters. |
| SHOW-VOLUME-ATTRIBUTES | The VOLUME-GROUP= operand defines the volume group to which a tape must belong to permit its catalog entry to be displayed. |
| MARENADM statement | Meaning |
| FREE-VOLUME | The VOLUME-GROUP= operand defines the volume group to which a tape must belong to permit it to be released. |
| RETURN-VOLUMES | The VOLUME-GROUP= operand defines the volume group to which a tape must belong to permit it to be returned. |
| SHOW-VSNS | The VOLUME-GROUP= operand lists the archive numbers of all reserved tapes which contain the specified volume group in the catalog entry. |
The MAREN or MARENADM statements RESERVE-FREE-VOLUME and SHOW-VOLUME-ATTRIBUTES and the MARENADM statement SHOW-VSNS are used to output the name of the volume group in the S variable var(*LIST).VOL-GROUP.
Meaning for the MAREN user
MAREN labels tapes as related which have been created by HSMS/ARCHIVE with a logical connection. These can be processed together in MAREN and MARENADM statements.
However, in BS2000 other tape sets are also created, e.g. multi-volume sets or related FDDRL tapes. These can be combined in a volume group and processed together. Furthermore, tapes which were created using different programs can be combined in a volume group. For instance the tapes of an HSMS backup and an FDDRL backup of the same day. These could, for example, be stored as a group in a fireproof safe and later be fetched from there.