>
> 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.
I agree that the 7000's were too quick to market... Every time I asked MTI
about them, they were "in beta." For 9 MONTHS, for crying out loud?!?
However, after some initial (2 weeks reviewing documentation and UNDOCUMENTED
SCSI-lib configuration changes) trouble over a year ago, our Q47 with
DLT4000 drives has been working flawlessly. Our only complaint is with ADSM's
rather unintelligent handling of eject cart requests for this library. We
bought a DLT4700 for offsite backup management so we wouldn't ever have to
crack the library.
If you want cheap reliability, I'd say that the 4000's are certainly an option
for you, especially if lightning speed is not necessarily your overwhelming
criterion.
Also, just for fun, I thought I'd let you know that we're getting 17:8 com-
pression, on the average, for the drives. We get roughly 42.5GB on a cart.
Mark
--
============== See me at http://www.Tulane.EDU/~mjc ======================
============== See me at http://www.Tulane.EDU/~mjc ======================
Mark Justin Cecil | Tulane University | mjc AT mailhost.tcs.tulane DOT
edu
Systems Programmer | Computing Services | cecil AT eecs.tulane DOT edu
(504) 865-5631 x 2535| New Orleans, LA | http://www.Tulane.edu/~mjc
|
