Whenever you need to format, erase, or retension tapes, use the Device Manager. Also, use the Device Manager to change the compression mode for your tape drives, if they support compression.

You can have up to 7 tape drives connected to your host. You can also divide these tape drives into ``groups''. By default, SCO ARCserve/Open is installed with one group for each SCSI drive attached to your host.

If you use more than one group, you can take advantage of ``parallel streaming''. Parallel streaming means that you can have more than one job running at a time. For example, you could assign drives 1 and 2 to a group called ``GROUP1'' and assign drives 4, 5, and 6 to a group called ``GROUP2''. You could then have a backup job running at GROUP1 while a restore job runs at GROUP2.

If you attach multiple drives with one group, you will be able to take advantage of ``drive spanning''. Drive spanning means that, under the right circumstances, when one tape becomes full, the session will automatically span to the next drive in the same group.

Grouping tape drives has the following distinct advantages:

• You can have several backup and restore operations occurring simultaneously, one at each tape group configured for your system.

• When a backup session spans to the next tape drive, it will only span to a drive that belongs to the same tape group.
  

For information about setting up and configuring tape groups, see ``Configuring tape groups'' .

The rest of this chapter describes how to get information about tape devices, how to interpret this information, how to set up tape groups, and how to maintain your tapes.