Steven,

We two have been using BreeceHill libraries- ours are Q47's with DLT4000
drives and have been having much of the same problems from the sound of
what you have related... I wonder if the problem is the drive itself
(either DLT4000-7000) or if it is the library product itself. I would be
very interested in hearing about people who use either product, Q7's or
Q47's without problems...

We have replaced the libraries' system boards, drives, cables, connector
boards, and yes, power supplies. Eventually, we have had to have
multiple replacement libraries shipped to alleviate the problems. I am
not sure who or what to point the finger at, the units perform well when
they work, but we have had a ton of reliability problems. Our systems
are HP9000's-- the server unit is a T520, our clients are T500's and
other 800 series units.  I have been using DLT units with other systems
for years and have had nothing but relatively high performance and
reliability.  Kind of makes you wonder...


Robert Alexander
SHL/MCI Systemhouse
ralexander AT shl DOT com

 ----------
From: Steven P Roder
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: DLT7000 drives with ADSM
Date: Monday, July 28, 1997 7:48AM

On Fri, 25 Jul 1997, Pittson, Timothy ,HiServ/NA wrote:
>
> I'm looking at throwing some additional hardware at our ADSM server.
> We're currently using a 3494 with 2 3590 tape drives and have been very
> happy with the performance and reliability.  However, my management
> won't go for another 3494 frame with additional 3590's because of the
> cost.  This leaves me with DLT and 3570 technology as options.  Anybody
> out there in ADSM land using DLT7000 drives  ??  If so,   have you been
> happy with the reliability, performance, etc.  Any gotchas I need to
> watch out for ??

I mulled responding to this over the weekend, and the continued problems
have made me decide to say something here.  I received two BreeceHill
Q7's
with DLT7000 drives in them back in May, and they are still not working
reliably.  First, I had problems with PTI's differential scsi card,
which
prevented me from writing to the drives (scsi adapter errors).  We got
rid
of the PTI boards, replaceing them with differential cards from Sun.  We
then proceeded to get read errors auditing the volumes created.
BreeceHill sent me out new firmware, a replacement drive, and a
replacement power supply, and the errors persist.  I have seen similar
problems accross both Q7's.  The problem seems to crop up as a
calibration error, which then causing subsequent reads to fail.
BreeceHill has now involed Quantum in this, so maybe it will eventually
get fixed.  I think there are still bugs in the firmware and drives
relating to calibration and head positioning.  I do not see this being
resolved anytime soon.  If I were to make a recommendation to management
such as you, with my experiences so far with the DLT7000's, I would tell
them to bite the bullet, and buy more 3494/3590 technology.  In my
opinion, the DLT7000's were rushed to market, and are unusable in their
current state.  They should still be in the lab, not in customer shops.

Also, when these errors first came up, I opened a problem with IBM's
ADSM
support, thinking that the problem may be with their device drivers.
After getting some traces, IBM said it was hardware, not software.  I
had
an extremely difficult time convincing the hardware vendors that they
had
a problem.  Throughout this whole ordeal, I have kept IBM in the loop,
and
I would like to say, publicly, that the ADSM Level 2 support team has
done
an outstanding job with this problem.  I do not know how anyone could
bash
their support services, as was done on this list.  My experiences with
ADSM support have been nothing short of outstanding, partciularly Larry
and Andy.

If anyone else is using DLT7000's, and can say that they work, I would
love to hear about it!  If anyone else is using DLT7000's with similar
problems to mine, I would love to hear about that too!

Steve (unVMix Systems Programmer/Dude) Roder
(tkssteve AT ubvm.cc.buffalo DOT edu | tkssteve AT acsu.buffalo DOT edu |
(716)645-3564 ,
   | http://ubvm.cc.buffalo.edu/~tkssteve)