Device Notices

This section provides information about the devices used for Backup data operations.

Nonrewinding Device Requirement

You must use a nonrewinding device for Backup backups. Backup writes a file mark on a volume at the end of each backup. When the next backup occurs, Backup appends data to the volume based on the position of the file mark.

If the device automatically rewinds the data, the file mark position is lost and the data is overwritten by the next backup; you will be unable to recover the previous backup data at a later date.

Hints and Tips for Specific Autochanger Models

This section provides tips for how to use and configure several supported autochanger models.

Tips for the Optical Autochanger

• If your optical autochanger does not work with Backup, your operating system may not currently include support for the optical autochanger media drive.

• When you create the Backup device names for an optical autochanger, you should use the raw name of the device.

• If you experience a power outage, the optical autochanger loses track of the state of its backup volumes. Issuing the nsrjb -H command may not successfully reset the autochanger. If you see output similar to the following, it means the nsrjb -H command failed to reset the autochanger:

# nsrjb -H
nsrjb: Autochanger error, Invert operation not supported

Use the following procedure to reset the autochanger:

1. Enter the following command, and make a note of the output.

   # nsrjb -H

   This command displays information about the volumes loaded in the drive(s), the volume label(s), and the slots from which the volumes were loaded into the drive(s).

2. Manually unload the volume from the device.

   Consult your autochanger hardware documentation for information on how to do this. The volume ends up in the cartridge access port with the "B" side facing up.

3. Manually reinsert the volume into the cartridge access port, flipping them over so that the "A" side faces up.

4. Use the control panel on the autochanger to reload the volume from the cartridge access port into the slot it originally came from.

5. Reset the autochanger.

   # nsrjb -H

Tips for the ADIC 1200c Autochanger

Unlike most autochangers, the ADIC 1200c does not allow you to set the SCSI address of the autochanger (robotic arm) and the tape drive separately. You can only set the SCSI address of the tape drive. The SCSI address assigned to the autochanger is always three numbers higher than the tape drive address.

Tips for the HP C1533A and HP C1553A Autochangers

The following information applies specifically to the use of an HPC1533A or HP C1553A autochanger with Backup.

• Dip Switch Settings

  To ensure that the HPC1533A and HP C1553A autochangers function correctly with Backup, refer to Technical Bulletin 144, obtainable from the Legato web site (http://www.legato.com/support/bulletins). The option switches are located on the underside of the drive.

• Transfer Rates with Solaris Systems

  If you experience poor transfer rates on an HP C1553A for Solaris system, refer to Technical Bulletin 142 for instructions.

Tips and Suggestions for the EXB-60 CHS

The following tips and suggestions apply specifically to the use of an EXB-60 CHS with Backup.

• The slot and drive addressing in the EXB-60 CHS is as follows:

  

• The EXB-60 CHS has the "element status" feature. Keep the autochanger loaded with volumes to optimize the inventory process.

  If you insert or replace a volume in a slot, you must issue the nsrjb command with the initialize element status (-E) option to update the autochanger inventory. If the device encounters an empty slot during the inventory, it rechecks several times to make sure the slot is truly empty. This can increase the time it takes to inventory the slots.

Tips and Suggestions for the EXB-120 CHS

The following tips and suggestions apply specifically to the use of an EXB-120 CHS with Backup.

• The slot and drive addressing in the EXB-120 CHS is as follows:

  

• If you install less than four media drives in the EXB-120 CHS, you must install the drives in the first physical positions in the autochanger. For example, if two drives are to be installed, they must be placed in the first and second positions. If three drives are to be installed, they must be placed in the first, second, and third positions.

• The EXB-120 CHS has the "element status" feature. Keep the autochanger loaded with volumes to optimize the inventory process.

  If you insert or replace a volume in a slot, you must issue the nsrjb command with the initialize element status (-E) option to update the autochanger inventory. If Backup encounters an empty slot during the inventory, it rechecks several times to make sure the slot is truly empty. This can increase the time it takes to inventory the slots.