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From: | |
Reply To: | Genute, Thomas |
Date: | Tue, 15 Dec 1998 13:07:36 -0500 |
Content-Type: | text/plain |
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We had lotsa problems with DDS2 drives. Most of the problems went away when
we put each drive on a separate card.
-----Original Message-----
From: Jeff Woods [mailto:[log in to unmask]]
Sent: Friday, December 11, 1998 12:08 AM
To: [log in to unmask]
Subject: Re: DDS-3 Troubles
At 10:26 AM 12/10/98 -0500, Russ Kahler wrote:
>In the last few months, we have had continued problems with
our DDS-3 tape
drives. On both of our HP 3000's ( a 967 and 928) we have
experienced a
serious, sudden drop in throughput on our nightly backups-
from about 1400
kb/s to around 1100 kb/s (causing the backup to take up to 1
1/2 hours
longer). This has happened three times to each of our three
DDS-3 drives in
the last 4 months- with no obvious hardware or software
errors ( the Scsi
card and cables are good, there is no increase in amount of
data stored,
and all system resources check out during the backup). It
just seems to hum
along fine for a few months, and then all of a sudden, the
next morning my
backup is taking an hour longer than it did the day before.
>
>Has anyone out there had any experience with problems such
as these? I
know tape drives wear out ...but every three months seems a
little excessive.
Repeated recoverable errors will both slow down writing to a
tape
considerably and reduce its effective storage capacity.
Perhaps this is
happening on a handful of your backup tapes. I suggest
testing this
hypothesis by reusing the same tape(s) noting how long each
takes to fill
and, if possible, how much data gets written on each tape.
If some seem
consistently slower or to handle significantly less data
than other media
of the same length (note that compression may complicate
determining this)
then I would get rid of them.
BTW, this behavior has been around a long time, even on the
old 9-track
reel drives. However, unlike DDS, DLT and similar media,
the visible reels
on 9-track drives could be seen (and usually heard) when
they started
handling rewrites due to recoverable (aka "soft") errors. I
suppose this
is yet another price of progress.
--
Jeff Woods
[log in to unmask] [PGP key available here via finger]
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