HP Archive Backup System for OpenVMS Guide to Operations

Saving and Restoring Data
3.1 Archives
3.1.7 Expiration Date and Retention Days
3.1.8 Location
3.1.9 Maximum Saves
3.1.10 Media Type
3.1.11 Pool
ABS supports two alternative methods of specifying when an archive expires. These are:
• Expiration Date - A date given in OpenVMS absolute time that defines a specific future date
that the volume data will expire.
• Retention Days - The number of days following retirement of the volume set that the data
will be retained, after which time it will expire.
Either retention days or expiration date may be given, but not both. By default, ABS defines
retention days of 365, meaning that volume data is valid for one year after retirement of the volume
set.
For an archive type of TAPE it defines the initial scratch date of the tape volume set. Once a volume
has transitioned to FREE state and it has been re-used all catalog entries relating to the past
usage of this volume are deleted. You can change the expiration of the archive by setting a new
scratch date for the volume. Whenever data is added to the volume set a new scratch date will be
set if the expiration date extends beyond the old scratch date.
For an archive type of DISK it defines the time at which the on-disk saveset is deleted. At the
same time all catalog entries relating to that saveset are also deleted.
Expiration date and retention days are only applicable to an archive type of TAPE.
ABS supports save requests that sometimes perform full backups and sometimes perform incremental
backups. Under these circumstances, it is useful to use different volume sets with different
retention days or expiration dates for the fulls and the incrementals. To support this, ABS
allows you to specify two archives for save requests: the first applies to the full backups, and the
second applies to the incremental backups.
A location is an MDMS object that defines the physical location of volumes, drives or jukeboxes.
The location is used as one of the selection criteria (along with media type) for allocating
a drive to load a scratch volume to extend the archive. If no location is specified for the archive,
ABS uses the default onsite location defined in the MDMS domain. This is the default. Location
is only applicable to an archive type of TAPE.
ABS supports multiple parallel save operations using a single archive, each operating on a different
drive and volume set (archive type TAPE). To enable this feature, specify the maximum
number of parallel saves that are desired using the maximum saves attribute. Values can range
between 1 and 36, with 1 being the default. This attribute also applies to an archive type of
DISK, but without the implications of multiple drives and volume sets being allocated.
Media type is an MDMS object that describes the type of tape media to be used in the archive.
Specify a media type that is defined within MDMS, or use the default domain media type. The
media type is used as a mandatory selection criterion (along with optional pool and location) for
volumes to be used in the archive. Media type is only applicable to an archive type of TAPE.
A pool is a logical MDMS object that relates a collection of volumes to a set of authorized users.
In this way, you can allocate a collection of volumes to certain users knowing that other users
cannot use volumes from the pool. Similarly, you can assign a pool to an archive, so that all volumes
used in the archive must be taken from the volumes that are in the pool. You can specify
3-4 Saving and Restoring Data