Using Alternate Backup Sets

As tape technology advances, tapes can hold increasing amounts of data. This increased capacity, and the increased cost of individual tapes, makes the ability to put several save sessions during the day on one tape volume extremely attractive to users. This ability is referred to as tape stacking.

Robot Save offers an option that allows you to make use of the new, high-capacity tapes. By specifying an alternate backup set, you can override the save media information for one or more backup sets to use a single backup set. This allows you to use the rotations for the alternate set for your backups. For example, you might do this if you back up your journal receivers every three hours.

As a safety precaution, each backup set normally should have its own tape rotations. However, using an alternate backup set allows Robot Save to handle multiple backup sets using the same tape rotations. The Extended Backup Set Information panel contains a field, Use Save Media of Alternate Backup Set, that lets you specify an alternate backup set name. The alternate backup sets can be from different classes.

For example, the following scenario describes how you could save journal receivers three times during the day to the same tape volume.

  1. Set up the first backup set to run during the day and name it JOURNAL1. Schedule the backup set on Robot Schedule to run at 10:00 a.m.

  2. Set up the second backup set to run during the day and name it JOURNAL2. JOURNAL2 must have the same number of rotations and days between rotations as JOURNAL1. Enter JOURNAL1 in the Use Save Media of Alternate Backup Set field. Schedule this backup set on Robot Schedule to run at 1:00 p.m.

  3. Similarly, set up the third backup set to run during the day and name it JOURNAL3. Enter JOURNAL1 in the Use Save Media of Alternate Backup Set field. Schedule it on Robot Schedule to run at 4:00 p.m.

When the second or third backup set runs, it will search for the end of the data on the tape and write from that point forward. The tape remains loaded after each save.

Notes:

  • To manage backup sets, Robot Save automatically updates the rotation code for any backup sets that were skipped to the rotation code of the current set. This process is called leveling. When you use alternate sets, the rotation code is leveled based on the rotation code of the primary set. For example, if you want to use rotation 2 of an alternate set, you must first mark the rotation code of the primary set to 2. See the section, Marking the Next Set/Rotation to Use, for information on how to change the rotation code.

  • You must run the first (or primary) backup set before running any of the other sets that point to it.

  • If a backup set has already been run, you cannot modify its definition to point to the media of an alternate set. A child (or secondary) backup set cannot have volumes already attached to it. Thus, if a backup set has been run, Robot Save will have attached volumes to the set’s rotations and the set cannot point to an alternate set.

  • A child (secondary) backup set always must load the primary (parent) set’s first tape until it is full. Make sure the volume is available to the child set. If you attempt to use another volume for the backup, unpredictable results may occur.

  • If you are using move sets, define the move set on the primary (parent) set only.