I can not stress that you need HP/Compaq hardware services engaged quickly.
From your problem description, I suspect you are experiencing 2 separate
problems which are corrected by drive swapping and/or firmware upgrades with
HP/Compaq SDLT libraries and drives:
There are known problems with older SDLT 110/220 drives where continuously
recycling previuously used tapes, and normal drive wear will cause the drive
rollers to "pinch" the outside of the tape while passing through the rollers.
Compaq/HP has the backend technical expertise to analyze the tapes to determine
if this is really happening. I have been told there are 2 generations of fixes
for this problem, though we do not recycle tapes much yet.
The second problem is known as calibration. It is also known within the
compaq/Hp circles as the V035 firmware issue. Brand new tapes when inserted
into a SDLT drive, have a calibration written to the pre-leader of the tape. A
strictly v035 firmware issue is the intermittent writing of a corrupt
calibration area. After this event, the tapes become totally useless in any
SDLT drive. These tapes can not be tar'd or cpio'd to or written in any method
we have tried besides legato. This is strange because you can insert the tapes
into the library, and then perform a label, and they appear to label correctly
some times, but then you can not write to them. I have had a HP/compaq tape
drive diag "ltt" installed, and with this you can read the internal tape drive
diags and events revealing the calibration problem. I have several tapes being
analyzed as I write this now expecting report this week. I upgraded to v051
and did not seem to have any more labeling issues, though other issues with
unknown relationships do still exist. This week, I upgraded drive firmware
again to v075 which appears to be a pre-release version while the jury rests.
My drives are quantun rebadged to hp/compaq. All of my media is fujifilm,
though we swapped to sony tapes a few months ago, they are fujifilm rebadged.
We were experiencing a 20% tape failure on labeling operations or with tapes
just labeled.
ps I also have a legato call opened, where the legato technician's
recommendation was to increase default tape load, and unload timers and double
tape cleaning intervals.
pps You mentioned tape cleanings. This is a very touchy subject which I will
discuss briefly. The original SDLT spec seems to imply cleaning are not
required. Interestingly you can by SDLT tape cleaning cartridges. Legato wants
the tape drives cleaned, and regularly. Me, I will let the big boys fight it
out, but do remember that a tape cleaner is the same as dragging sand paper
over the tape heads.
-----Original Message-----
From: Steven Frost [mailto:Steven.Frost AT POWERCO.CO DOT NZ]
Sent: Tuesday, October 28, 2003 6:11 PM
To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
Subject: [Networker] SDLT tape reliability.
Hi there. I am finding that the attrition rate on our Super DLT tapes seems
rather high.
For tape that is purported to last 1,000,000 passes , we should not have ANY
media problems.
For example , a volume previously had 250GB+ written during the normal
savegroup process and was marked as full
without errors. On it's next cycle a media I/O error happens after, say, 25GB,
and Legato uses another
volume from the jukebox inventory. The tape with the media error is now useless
( after 25GB anyway).
Is this normal?
Our volumes at most would only have 20 saves done over the last 18 months, as
we have had our SDLT drives since April 2002, and the tapes are re-used
monthly. Out of 140 cartridges, nearly 22 are now dodgy. Is there a way to
rejuvenate these?
We have had dual Compaq/HP SDLT 160/320 drives in a Compaq MSL5026 Jukebox
since November, beforehand they were 110/220 drives. We have replaced one of
these drives twice now , as there were too many tape problems. If a tapedrive
is 'shoeshining', would that affect the tape media?
Any comments or similar experiences ? Thanks .
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