If your tape pools are collocated, try turning collocation off. Using
collocation causes a lot more start/stop, positioning, and append activity
on the tapes.
In my experience, if you have a drive that is at all flaky, the extra
indexing/positioning will exaggerate the problems and increase the number of
I/O errors in a high-activity system.
Also LOOK at the drives themselves and watch the CLEAN light on the drives.
Make sure your drives ARE getting cleaned regularly when the clean light
comes on.
Make sure you have a NEW cleaning tape. Unlike some other cleaning tapes,
when a DLT clean tape is used, it writes a tape mark 1/20th down the tape.
The next clean uses up 1/20 more tape. When you have used it 20 times,
putting it back in the drive doesn't clean anything. You can degauss it to
erase the tape marks and then reuse it up to 3 times.
If you put in a GOOD clean tape, but the clean light doesn't go out, it
means you are getting weak signal strength because the heads aren't aligned
right with the data. If you clean the drive and the light goes out, but
later you see the clean light come on frequently anyway, it's because you
are getting tapes written on one drive that can't be read on the other. In
either case, make the vendor replace the drive. We had several drives get
flaky this way - they would call for cleans over and over, create data that
couldn't be read back, but never fail hard. That happened over time as the
drives aged, though.
We had one TSM server with a very high load that had constant problems of
this type, where the other TSM server with a very modest load and exactly
the same software/hardware setup had no problems with the DLT drives at all.
Both were AIX with DLT, though. No experience with DLT on an NT system.
My opinions and nobody else's,
Wanda Prather
> -----Original Message-----
> From: Dennis Berestecki [SMTP:[EMAIL PROTECTED]]
> Sent: Tuesday, October 10, 2000 10:14 AM
> To: [EMAIL PROTECTED]
> Subject: Damaged Tapes using TSM 3.7.2 for NT and DST Tape Drives
>
> This appears to be an old subject, but it is new to me.
>
> We have an IBM Netfinity 7000, with 3 Adaptec 2944UW SCSI adapters,
> running
> Tivoli Storage Manager 3.7.2 for NT, attached to an ATL P3000 robotic
> library, with six DLT7000 drives. We converted from Arcserve in June,
> 2000.
> Over the course of the last 2 months, or so, we have had at least 40 tapes
> come up with damage. I/O errors, read errors, write errors, READONLY and
> UNAVAILABLE access, etc. We have used brand new tapes, relatively new
> tapes, and some quite old tapes in this machine. Some of the tapes were
> previously used as Arcserve (both Novell and NT) tapes in both DLT4000 and
> DLT7000 drives.
>
> I have had to perform numerous RESTORE VOLUME processes, to restore the
> data, some of which have required me to load as many as 35 OFFSITE tapes
> for one restore. The process is consuming LARGE amounts of my time, not to
> mention the wear and tear on the robot. We bought the P3000 specifically
> because we already had a large investment in DLT media, but it appears
> that
> this may have been a fatal decision. In some cases, the RESTORE VOLUME has
> failed because the OFFSITE tapes are also damaged. This is continuing
> through today. I have to load 32 tapes to restore a tape that came up
> damaged yesterday.
>
> ATL has upgraded the microcode on the drive twice in the last 2-3 weeks,
> first to rev. 97, then to rev. 101. We have also had a number of the
> drives
> replaced since we first went online in June. It has been suggested that
> the
> "speed" settings on the 2944UW's may be too high. They are default, 40.
> Are
> there any special settings that this setup may need, whether it is SCSI,
> TSM server, or whatever? This is really beginning to drive me crazy!
> Tivoli
> support has been helpful, but they have offered no information that might
> resolve this. ATL has been willing to swap parts and upgrade firmware, but
> they have been in denial of any responsibility for the problem. I want a
> Magstar!!!
>
> Dennnis Berestecki
> [EMAIL PROTECTED]
> 281.263.2196
>
>
>
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