General Information

The archival and backup functions assist you in managing your online storage, but the copies in the archives (and the index entries for them) must also be managed. This section describes the utilities and procedures that provide you with the ability to do so.

CA Disk combines the data sets being archived (or backed up) into a single output data set. This output data set is in sequential format, and therefore can be placed on a standard tape, a tape cartridge, or any disk device. Since archive and backup functions have traditionally directed their output to tape, the output data set has also corresponded one for one to an output volume. This has led us to think of them as archive volumes, with CA Disk keeping track of them in an archvols index. But keep in mind that each is really just a sequential data set that can be on either disk or tape.

Whenever a data set needs to be restored, rapid access into the archvols data set is desired, regardless of whether it is on disk or tape. To provide this ability, CA Disk also maintains an index to each of the archived data sets. The index entry contains the exact location of each archived data set within the single archvols data set.

In the following discussion, any reference to an archive volume refers to an archvols data set, which can reside on either disk or tape, and can consist of backup and/or archive copies of numerous data sets.

Each data set in the CA Disk archives has its own expiration date (assigned by the requestor or an installation default), and CA Disk is designed to manage the archives by examining this date for each data set. Since the expiration date for each data set is the controlling factor, CA Disk default processing assigns all of the archive volumes (tapes or disk data sets) the never expire date of 99365. When CA Disk determines that all of the data sets on an archive volume have expired, the archive volume will be deleted/expired as well.

When a data set's expiration date is less than or equal to the current date, the data set is considered expired. Consequently, an archvols data set can contain expired as well as unexpired data sets. When an archvols expiration date has passed, all of the data sets contained within it should also have expired. At that time, or shortly thereafter, all of the corresponding entries should be removed from the CA Disk archive index. If the archvols data set was on tape, the tape should be put back into the scratch pool. If it was a disk data set, it should be deleted.

Given this situation, the following items describe the most common tasks dealing with files data maintenance:

The most common task can be to simply list the archive volumes and/or the names of the archived data sets.
Perhaps the most important task is to delete index records for expired data sets from the DSNINDEX subfile. This process both frees up space in the subfile and releases archive volumes when all data sets they contain have expired.
Combine two or more partially used archvols into more fully used archvols. A partially used archvols can consist of a tape that had very little data written to it, or it can be a tape or disk archvols data set that contains many expired entries. The unexpired entries are combined onto a new archvols data set that is more fully used, freeing up either disk space or tapes to be returned to the scratch pool. Detailed information regarding this facility is contained in the chapter "MERGE."
Delete data sets from the archives regardless of their expiration status. Normally this is done on an as-requested basis to satisfy a specific need (that is, delete obsolete data sets from the archives).
Delete archvols from the archives, regardless of their expiration status. This can be done when a tape volume becomes lost or unusable. At the time the tape volume is removed from the archives, all index records pertaining to data sets that existed on the tape must also be deleted.
Make a copy of an archvols data set for backup purposes. CA Disk records the presence of a copy archvols such that it can be used when a primary archvols becomes unusable. This can be done automatically by certain functions, such as Archive, Merge, Xcopy, or it can be done at any time by specific request.
Change the status of data sets by changing control information for them in the archive index. Users may want to change the expiration date of a non-SMS data set in the archive index. It may need to be either extended or reduced.
Rebuild index entries from an existing archive data set (on either disk or tape), into the CA Disk archive index. This can be useful in transporting data to another CA Disk system, or to recover archive index data in the event it is lost.