Topic: DLT Tape drives?

[Dan Brown]

The consensus around here seems to be that just about any SCSI tape drive should work with SME 5, but I'm curious.  The listing in the manual doesn't include any DLT drives, and hardware.redhat.com seems to be down at the moment.  I'm starting to see 40/80 GB DLT drives at pretty reasonable prices, and my understanding is that DLT is a pretty robust format.  Does anybody have any experience using DLT with e-smith/SME?

[Robert Boerner]

I haven't had a chance to try DLT with e-smith, but I can give you my two cents on the format in general.

I deal with many drives all of the country, and a lot of them have failed. By failed I mean pure hardware failure. I have not had a restore error (yet).

I have had several drives have fail due to what I believe are design flaws. Most of my drives came from Compaq (which are rebranded Quantums I believe) and the mechanism which pulls the tape from the cartridge can fail if the tape leader isn't positioned properly in the tape cartridge. We were having drives swapped out under maint. agreements, but one day someone took one apart and found out it was simple to reposition the mechanism. Very annoying when your 4,000 tape drive fails because someone did not take to time to better engineer a 15 cent part.

I am curious about and would love to hear anyones experience with the Ecrix line of drives.

[Dan Brown]

Well, hardware.redhat.com is back up, so I was able to find some information: it looks like Dell DLT4000 and DLT7000 drives (which are just rebranded Quantum units) are "certified" w/ RedHat 7, and DLT1 drives are listed as "compatible".  Sounds like a good sign.

BTW, when I say "pretty reasonable prices", I mean refurbished DLT1 drives (40/80 GB) for $500 or so.

Does anybody else have any experience with the format, whether under e-smith or not?

[Jeff Coleman]

We've used a number of DLT drives and frankly I'm not impressed with their mechanical performance.  We have had to send a number of them back for repairs.

If you can afford it, I'd reccommend looking at the AIT drive standard.  More capacity and definately more stable hardware.

-jeff

[Dan Brown]

Interesting--what I'd heard about DLT in the past had generally been positive.  Of course, my only real experience has been with QIC/Travan devices (might as well just pipe the data to /dev/null as far as restore reliability is concerned), so just about anything would be better.

How long has AIT been out?  Does anybody know of a reasonably-impartial comparison between DLT and AIT (and other competitive technologies, if any)?

[Jeff Coleman]

Dan,

Here are a couple of links that may be helpful:

http://www.newwavetech.com/pdf/Spectralogic/Microsoft%20PowerPoint%20-%20AIT%20vs.%20DLT.pdf

http://www.networkcomputing.com/1007/1007buyers3.html

-jeff

[Dan Brown]

Thanks for the links, Jeff!

[Ron Gillies]

I have been using a Quantum DLT for the past two years as one of my backup
systems --- first on an NT box and now under Esmith.

I have not encountered any hardware problems (touch wood) and have found
that I can rather easily copy data from both my servers over without much
problem.

Daily incremental backups go to a CDR but to back up about 20GB of data
(could be restored from a stack of CD's without problem but a single DLT
is much) I use the DLT.

I picked mine up at an auction for a very good price two years ago and have
been quite happy.

Hope this helps

Ron Gillies

[Dan Brown]

Over the weekend, I thought of another, sort of off-the-wall question: has anybody tried sharing a tape drive via the SCSI bus?  That is, go from computer to tape to other computer via SCSI.  This is perfectly legal as far as the SCSI bus is concerned (as long as you set the ID of the HBA on one of the computers to something other than 7), but I don't know how the computers would react to something like this.

[Pierluigi Miranda]

Robert Boerner wrote:

> I haven't had a chance to try DLT with e-smith, but I can
> give you my two cents on the format in general.

I don't know if what I'm writing below is even two cents worth, but let me say it anyway...

> I have had several drives have fail due to what I believe are
> design flaws. Most of my drives came from Compaq (which are
> rebranded Quantums I believe) and the mechanism which pulls
> the tape from the cartridge can fail if the tape leader isn't
> positioned properly in the tape cartridge

We are using older Digital TK and newer DLT tape drives for more than ten years now; while in my experience TK drives tend to malfunction if left unoperable for long periods of time, no DLT drive showed any mechanical problem in years of rather intense use.

A word of explanation: DLT tape drive are descendants of the Digital TK tape drive series: the cartridges and tapes are physically the same (but the magnetic substrate and tape thickness are not, so as the recording standards), and some DLT models are TK compatible, letting one read TK cartridge. I guess that DLT technology born at Digital whell before Quantum "spinoff"...

The only tape jam case we experienced was caused by loading a cartrige that had been tampered with and so the tape loading ring was misplaced.

All TK and DLT cartridges are extremely dependable, remaining readable even after years of (not so careful) storage. Besides, DAT dependability is questionable: sometimes a DAT tape pass the verify phase after a backup, just to discover it corrupted after a couple of weeks...

--

Pierluigi Miranda