Compaq ProLiant 6000 Compaq DLT Tape Array II: High-Performance Backup of Ente - Page 33

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DLT Tape Array II

ECG075.0997

A

PPENDIX

1:

T

IPS FOR

C

ONFIGURING AND

O

PERATING THE

C

OMPAQ

35/70 GB DLT D

RIVE

The cables provided with the various Compaq option kits are of very high quality. If they are

ever damaged, replace them with identical Compaq parts. SCSI data transfers will operate

poorly (or not at all) when signal conditions are degraded due to low-quality cabling.

Always screw the external cable heads into the SCSI cards and DLT Tape Array II chassis to

prevent damage to the connectors and possible loss of data.

If using an embedded SCSI controller to drive a single 35/70 GB DLT drive, ensure that it is a

Compaq 32-bit Fast-Wide controller or install a 32-bit Fast-Wide SCSI card to improve

performance. Use of a 32-bit Wide-Ultra SCSI-3 controller is

strongly recommended

if there

will be two 35/70 GB DLT drives per card. To identify the card, look at the main logic chip in

the center of the card and verify that it is a Symbios Logic 53c875 part. Cards with the NCR

53c825 part will not deliver maximum performance.

For high performance, install four DLT drives (typically using the DLT Tape Array II chassis),

connected by two cables to two 32-bit Fast-Wide SCSI PCI cards in the server. The drives can

be configured as four separate drives running four separate jobs, or one as a single RAIT group

running a single job.

Though performance may be better with a RAIT-0 configuration, RAIT-5 offers better

protection from data loss by striping the tape with additional checksum/recovery information.

For the highest margin of confidence, configure a set of mirrored drives (2x2 in one DLT Tape

Array II or two DLT Tape Array II devices for a 4x4 set). Mirroring makes full duplicates of

the tape and adds the advantage of storing tapes in two locations.

DLT drives have a “Use Cleaning Tape” indicator on the front panel. Clean the drive by

loading a cleaning tape (PN 199704-001). It will clean the drive, then automatically unload.

The cleaning tape is effective for 20 cleaning cycles. Do not exceed this. If a backup tape

causes

the cleaning light to come on (versus this occurring during a restore function) copy the

tape or recover it and stop using it. Such a tape can contaminate the drive, which may then

contaminate other tapes if the drive is not cleaned between loads.

Never

try to clean a DLT

drive with anything other than a cleaning tape.

To avert tape leader failures, wait two seconds after the green indicator turns on before

extracting a tape cartridge. Never move the drive while a tape is engaged. The tape moves past

the head at 170 inches per second; moving the unit while it’s operating can cause tape or drive

damage. It is also important not to drop or physically shock the DLT tapes. Doing so can

damage the tape, which in turn can damage the drive (as well as lose data). If the cartridge

appears damaged, do not use it. It is best not to risk damaging the drive.

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Compaq ProLiant 6000 Compaq DLT Tape Array II: High-Performance Backup of Ente - Page 33

Ppendix, Ips For, Onfiguring And, Perating The, Ompaq

Page 33 highlights