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How to Backup

Members of the ISP-Tech list discuss what media to use when backing up large amounts of data. There is no simple answer.

[August 4, 2000]

On the ISP-Tech list in July, RS brought up the issue of what media works best for backing up data when he asked:

"How many times should a tape be used for backup before it's retired?"

 

A number of respondents felt strongly that using tape is a mistake:

[KH responded] "We've had so many problems with tape that we concluded it just isn't worth the hassle. We're switching to removable Hard Disk Drives (HDDs)."

[JM agreed] "If you backup to an identical-sized HDD and you have a drive failure, you can be up in minutes, versus hours for a tape drive. My point is valid, I promise — I found out first-hand."

[TB added] "HDDs are relatively inexpensive in comparison to tape drives for the capacity you'll need today. A tape drive that holds more than 20 gigs will set you back at least three grand if not more. Backing up to HDDs is more cost effective, especially considering the time it takes to pull a single file off a tape backup."

Others contended that, as long as proper care is taken, tape backup is best:

[VB observed] "As far as restore is concerned, you have a good point about picking single files off the tape. But tape drives have been used perfectly reliably for mucho years. HDDs fail too, and tapes are a tiny fraction of the cost of HDDs. The short answer is, buy the best tape drive and media you can, keep everything clean, and use a reasonable rotation. As to the original question, I'd ask the manufacturer for the Mean Time Between Failure (MTBF) of their media. Some of my tapes are 4+ years old and still work perfectly."

[JL agreed] "If you're using appropriate tape backup software (we use Backup Exec) and it's properly configured, the software will tell you when you need to pitch the tape. There are three things to remember regarding tape, which I consider an excellent backup medium:

1. Always use backup software, which does an automatic verify operation during the backup process to be sure the recorded data matches the original data.
2. Always make two identical backups. It's highly unlikely that two tapes created using verify operations as described above would both fail.
3. Store tapes in a comfortable environment. If it's too hot or too humid for you, it's also too hot or too humid for magnetic media. Storage guidelines are available from 3M, the United States National Archives, and from professional standards organizations."

 —End