Improper tape storage handling frequently contributes to data loss. Dust, sudden impacts, and heat are just a few of the things that can render a tape unreadable. Curtis Breville, founder and president of geniusTek and the writer of the Web site AskMrStorage.com, discusses tape handling best practices in this Q&A. His answers are also available as an MP3 below.
Table of contents:
>> How does a tape drive write to tape?
>> Why do tapes require such care?
>> What are the most common causes of tape failure?
>> How can you prevent damage to tapes?
>> How should you store tapes?
>> What else do people need to know about tape handling?
A tape drive used for backing up data is not that different from the ones we had in our old boom boxes that we used to record and listen to music. There is a controller on the drive which spins the tape, moving it over the read and write heads. There is a buffer that holds data and adds protective error protection codes to the data that is written.
After the data is written on to the moving tape by the write head and then verified and compared to the data in the buffer by the read head, the data in the buffer is removed and another set of data fills the buffer. All of this happens in a matter of nanoseconds.
For linear tape formats such as LTO or DLT, the tape is written on tracks which extend the length of the tape. LTO-4 records almost 900 tracks per tape.
In the event of a tape failure, a company's ability to restore large amounts of data can be jeopardized. The maximizing of tracks on the tapes means that you have tracks of data out on the very edges of the tape. Damage to the edge of the tape can render that part of the tape unreadable and data would be lost.
Plus, the tape cartridge houses very delicate components that work to make sure the tape is wound properly, that it runs properly over the read and write heads, etc. Dropping a tape cartridge, squeezing it, or introducing it to extreme temperatures can damage these components.
Normal wear, such as the tape repeatedly coming into contact with a surface such as the read/write head over time can cause some damage. When tapes are handled by a backup administrator, the tapes can be dropped, stacked on top of each other in a metal box, or subjected to vibration that can damage the delicate components housed within the cartridge. There are also environmental issues. High or low temperatures, humidity, dust, can all lead to tape failure. Then there are winding errors which can result in the tape getting spun around inside the drive.
Holding them in your hands as little as possible is a good start. Transporting them in a secure transport designed specifically for the tapes themselves, for example the Imation DataGuard Transport and Storage Case, can reduce shock to the tapes if dropped, controls air pressure, and keeps dust away from the tapes. This will result in far less damage.
Keep your tapes away from foam padded cases. Foam generates dust that can corrupt the tapes. Do not store your tapes near or in cardboard boxes for the same reason.
Protective cases are necessary. Once they are in a protective case, ensure that the case is stored in an appropriate, climate-controlled environment, and handled gently with as little impact and vibration as possible.
Monitoring your tapes and tape drives with backup monitoring software will let you know if the quality or the performance of the tape or tape drive is beginning to degrade. This will let you know if data on a tape should be migrated to a new tape.
Twenty-year storage industry veteran, Curtis Breville, is the founder and president of geniusTek an analyst and consulting firm dedicated to intelligent IT strategies, and is the writer behind the Web site, AskMrStorage.com.