DLT tapes lifespan

[Rick Garland]

Hi all:

Looking for the lifespan of DLT tapes. Have found the info that states a shelf life of some 30 yrs with given climate conditions. Have also found the info concerning 500,000 - 1,000,000 passes.

How to equate this info to number of backups, hrs of writes, etc.

I have some DLT tape that are some 3 yrs old. Should I be concerned with replacing? If not now, when?

[Jeff Machols · Accepted solution]

Rick,

I have been through this with our tape dealer many times and not been able to get a straight answer. We just watch for tapes that get errors, or more often have performace issues. When we see a backup that is slower than normal, that's usually a sign the tape cis getting warn. Sorry theres nothing more solid...

[Darrell Allen]

Hi Rick,

I found this link (although it sounds like you've already seen it):
http://us-support2.external.hp.com/cki/bin/doc.pl/sid=56a19f5d0024ea043b/screen=ckiDisplayDocument?docId=200000056973393

According to the specs, you have nothing to worry about. We'll never use a tape half a million times. But in the real world? I've had a few problems with DLT tapes but not many. Many less problems than with DDS. What gripes me is you just don't know when a tape is going to fail.

Sorry I don't have stats.

Darrell

[Helen French]

hey,

The Quantum says " life of 30 yrs abd head passes in excess of 1 million passes " !!

You may get some more idea here: http://www.quantum.com/NR/rdonlyres/000001c4teqwkaneotewotxz/DLTtape_Drive_Reliability.pdf

HTH,
Shiju

[Jeff Machols]

From what I was told, the number of passes is not a one to one ratio to uses. Out CE calls it the shoe shinning effect, when a tape rewinds very slightly and read or writes again, just a few K worth of info. Each time that go back and reads again, its another pass. So if you have a dirty drive and the tape has to keep going back and forth to read the data, you can get hundres of passes on a single use. Now, half a million is still a lot, plus this guy may have made that up to keep my quiet, but that my 2 cents.

[Paula J Frazer-Campbell]

Rik

My backups sequence comprises of 31 tapes and each month I pull one out of the sequence and use it for the End of Month backup which is stored forever.

That way I never have a DLT tape older than 30 months in my sequence.

If I require a misc tape I also pull it from the backup chain and replace it with new.

So far no failures - 1 million passes Baa Humbug.

HTH
Paula

[Rick Garland]

Based on the spec of 500000 passes and if I am using the same tape daily - 7 day/wk (trust me, I am NOT doing this).

I get some 1340 days which would be over 3 yrs. Now I have some 25 tapes per client so if I am doing the math right, this would be approx 75 yrs. Am I looking at this right?

[Sanjay_6]

Hi Rick,

Try these links,

http://www.hp.com/cposupport/information_storage/support_doc/lpg50166.html

http://www.hp.com/cposupport/information_storage/support_doc/lpg50167.html

Hope this helps.

Regds

[Sanjay_6]

Hi DLT,

Sorry, missed this,

http://www.hp.com/cgi-bin/cposupport/get_doc.pl?SNI=hpsurestor24388&LC=information_storage&Tfile=lpg50139#P173_5443

Hope this helps.

Regds

[Timothy Czarnik]

Rick,

Not sure of the math, but its been my philosophy (with OmniBack anyway) that if the tape gets a read/write error that I can attribute to the tape, I verify it once and log this. If it does it again, I toss it. I know tapes aren't cheap ($75 per), but the potential harm that comes from a bad tape is worth the cost. I normally toss out a tape every 2 or 3 months.

I wouldn't stay up nights worrying about this. We won't be using tapes in a few years anyway with technology going the way it is. We'll be writing terabytes to DVD's or something similar.

Just my thoughts...

-Tim