Managing Tape Drives (Tasks)

This chapter describes how to manage tape drives in the Solaris™ Operating System.

This is a list of the step-by-step instructions in this chapter.

• How to Display Tape Drive Status

• How to Retension a Magnetic Tape Cartridge

• How to Rewind a Magnetic Tape Cartridge

This is a list of overview information in this chapter:

• Choosing Which Media to Use

• Backup Device Names

• Displaying Tape Drive Status

• Guidelines for Drive Maintenance and Media Handling

Choosing Which Media to Use

You typically back up Solaris systems by using the following tape media:

• 1/2-inch reel tape

• 1/4-inch streaming cartridge tape

• 8-mm cartridge tape

• 4-mm cartridge tape (DAT)

You can perform backups with diskettes, but doing so is time-consuming and cumbersome.

The media that you choose depends on the availability of the equipment that supports it and of the media (usually tape) that you use to store the files. Although you must do the backup from a local system, you can write the files to a remote device.

The following table shows typical tape devices that are used for backing up file systems. shows The storage capacity for each device depends on the type of drive and the data being written to the tape.

Table 52-1 Media Storage Capacities

Backup Device Names

You specify a tape or diskette to use for backup by supplying a logical device name. This name points to the subdirectory that contains the "raw" device file and includes the logical unit number of the drive. Tape drive naming conventions use a logical, not a physical, device name. The following table shows this naming convention.

Table 52-2 Basic Device Names for Backup Devices

In general, you specify a tape device as shown in the following figure.

Figure 52-1 Tape Drive Device Names

If you don't specify the density, a tape drive typically writes at its "preferred" density. The preferred density usually means the highest density the tape drive supports. Most SCSI drives can automatically detect the density or format on the tape and read it accordingly. To determine the different densities that are supported for a drive, look at the /dev/rmt subdirectory. This subdirectory includes the set of tape device files that support different output densities for each tape.

Also, a SCSI controller can have a maximum of seven SCSI tape drives.

Specifying the Rewind Option for a Tape Drive

Normally, you specify a tape drive by its logical unit number, which can run from 0 to n. The following table describes how to specify tape device names with a rewind or a no rewind option.

Table 52-3 Specifying Rewind or No-Rewind for a Tape Drive

Specifying Different Densities for a Tape Drive

By default, the drive writes at its "preferred" density, which is usually the highest density the tape drive supports. If you do not specify a tape device, the command writes to drive number 0 at the default density the device supports.

To transport a tape to a system whose tape drive supports only a certain density, specify a device name that writes at the desired density. The following table describes how to specify different densities for a tape drive.

Table 52-4 Specifying Different Densities for a Tape Drive

The additional density values are shown in Backup Device Names.

Displaying Tape Drive Status

You can use the status option with the mt command to get status information about tape drives. The mt command reports information about any tape drives that are described in the /kernel/drv/st.conf file.

How to Display Tape Drive Status

1. Load a tape into the drive you want information about.

2. Display the tape drive status.

   # mt -f /dev/rmt/n status

   
   

3. Repeat steps 1-2, substituting tape drive numbers 0, 1, 2, 3, and so on to display information about all available tape drives.