Troubleshooting DAT Drives -- Chapter 5 Cleaning DAT Drives and Autoloaders

First Edition September 1996
Document Number 244A/0996

Compaq tape drives are designed to operate reliably under worst case conditions; however, they require simple routine maintenance to operate efficiently. Regular cleaning is the most essential step in properly maintaining a tape drive and preventing errors. This chapter discusses the importance of cleaning, what happens when cleaning is not performed, how often to clean, how to clean, and how to schedule automated cleaning jobs.

Reliable backup of your system is the product of the following components:

• A reliable tape drive
• Quality tape cartridges
• Regular backup schedule
• Routine tape drive maintenance
• Automated cleaning for Autoloaders

Importance of Routine Cleaning

Routine cleaning of a tape drive minimizes buildup on the read/write heads so that fewer cleaning cycles are required to keep the tape drive in good working order. See the Recommended Cleaning Frequency table.

When a tape drive is cleaned according to a regular schedule, one cleaning cycle typically removes accumulated dirt and particle deposits. If the drive is not cleaned regularly, however, up to 4 cleaning cycles may be necessary to fully clean the drive.

Errors Resulting from Cleaning Neglect

Among the tape drives available today, DAT drives are some of the most susceptible to particle buildup. If a DAT drive is not kept clean, increased dropouts where the drive cannot read or write to the tape will occur. You may lose 20 percent of backup capacity and performance if the recommended head cleaning schedule is not followed. DAT drives monitor the total number of dropouts; when the number reaches a predetermined threshold, the green LED will slowly flash, indicating the tape drive needs cleaning.

These are some of the errors that can result from failure to observe routine maintenance and cleaning of tape drives:

• Dropouts. Caused by weak signal strength from dirty read/write heads, a dropout can result in reduced tape capacity and backup performance.
• Media errors. The backup tapes can be jammed, torn, or otherwise damaged by a dirty read/write head.
• Read or write errors. Because of a dirty read/write head, data may not be recorded on the tape during backup. Even if the data is on the backup tape, retrieval may not be possible if the dirty head cannot read the data.
• Format failures. During backup, data is laid on the tape in a certain format for easy retrieval. A dirty write head can cause format failures, which means that data can be lost or impossible to retrieve.
• Bad blocks. Because of media damage (see Media errors above), the tape may not accept backup data. Also, the read/write head may be unable to retrieve data from bad blocks.

Recommended Cleaning Frequency

To optimize DAT performance, follow these recommendations for cleaning:

• When using new tape media for backups, DAT drives need to be cleaned after each 8 hours of read/write operation until the entire data cartridge has been used 5 times.
• When using data cartridges that have already been used 5 times or more, clean DAT drives after each 25 hours of read/write operation.
• Clean DAT drives before performing a complete server backup.
• Clean only once for routine cleaning, to minimize head wear. Occasionally a single cleaning cycle will not fully clean read/write heads on a DAT drive. If the backup software reports errors, clean the drive to eliminate the possibility that dirty heads are causing the error.
• Clean 4 times after a failure to ensure the heads are cleaned. A single clean may not remove a head clog.
• When using a TurboDAT AutoLoader, keep a cleaning cartridge in the last slot. Refer to your software user manual for instructions on how to schedule and perform cleaning operations using the software application. Also, refer to the section below on automating a cleaning cycle.
• DAT cleaning cartridges typically last 30 cleaning cycles (passes).
• Use only the cleaning cartridge to clean the heads.

CAUTION: Do not use alcohol or cleaning solution to clean DAT drive read/write heads. To avoid damaging a DAT drive, do not clean read/write heads with a cotton swab. Fibers from a cotton swab can cause permanent damage to the head. Only the cleaning cartridge must be used to clean the heads.