Tape Cleaning

[clay bowman]

I'm recieving cyclic redundancy check error messages during my backups at almost all my sites, using Backup Exec 9.1 I'm attaching an article from HP that recommends cleaning the heads 5 times. My question is: Should the heads be cleaned more often instead of waiting for the light to come on? I know before it was recommended to wait for the light.

[Michael Tully]

I've always followed the guideline of waiting for the light to come on. I've found that cleaning any more than that causes the heads to wear out prematurely. You see the cleaning uses an abrasive substance, so cleaning more frequently than required can cause drives to die an early death. Usually cleaning drives a lot (when the drive asks for it i.e. the light being on) is an indication that the drive is soon in need of replacement.

[David Ruska]

Are you talking DDS or DLT/LTO?

I suspect you're talking about DDS, where cleaning 5 times in a row is recommended if you haven't been doing regular cleanings.

For DDS, the recommendation is cleaning after every 5th full backup, or 25 hours of use. DDS cleaning tapes are not abrasive to the head.

For DLT, Michael is right - only clean when the drive requests it. DLT drives are generally self-cleaning if they are kept streaming, and in a clean environment. The DLT cleaning tape IS abrasive to the head. A few hundred cleanings and the head probably will have significant wear.

For LTO, again clean only when required. The HP LTO drives, they are bit smarter - if you load a cleaning tape when the light is not on, and the drive had been cleaned in the last few hundred hours, it will not actually do a cleaning. The HP LTO drive also has an internal cleaning brush that cleans the head.

[clay bowman]

I'm talking SDLT, and if it takes a few hundred cleanings to destroy the drive, that would put me put out 20 years if I clean once a month, I doubt 110/220 drives will still be used then.

[David Ruska]

> I'm talking SDLT

Sorry, I skipped that one. The story is the same as DLT. I quote Quantum directly:

"Do not clean your drive unless cleaning is indicated."

"SDLT drives may not require preventative cleaning, because of improvements in the head design. The frequency of cleaning is dictated to a large degree by the amount of ambient pollution and particulates in the environment".

Here's the Quantum manual, if you want to read more...
http://www.quantum.com/pdfs/sdlt220_sdlt320_product_manual.pdf

So again, the tape is abrasive so you only want to use it when necessary. It's like cleaning your bathtub with comet. After a while - there's no finish left.

> and if it takes a few hundred cleanings to destroy the drive, that would put me put out 20 years if I clean once a month, I doubt 110/220 drives will still be used then

I don't know what the magic number is for SDLT. However, in between working and being worn out from overcleaning, your soft error rate will go up, and your performance/capacity will go down. Follow Quantum's advice - clean only when requested.