muenzel@wega.tat.physik.uni-tuebingen.de (Stefan Muenzel) (10/30/90)
Once more a problem with the EXA-Byte: We have a EXA-Byte 8200 and want to use it with a SGI 4D/20. But when we try to tar some bytes we get messages like the following: Oct 22 18:05:04 mira unix: NOTICE: SCSI tape #5 Uncorrectable media error Oct 22 18:05:04 mira unix: NOTICE: SCSI tape #5 Unrecoverable error Oct 22 18:05:04 mira unix: NOTICE: SCSI tape #5 had 2215 recoverable Errors (Copied from the SYSLOG-file). This occures after some 100 kbytes. Our first guess was, that we had bad tapes, but we've tried several new ones from Sony and Exabyte. It seems not to be a problem of the SCSI-bus, since there are no errors like ' sc0: Unexpected info phase, state 48 phase 46' or ' sc0,1: Resetting SCSI bus: stray interrupt error, phase 0x46, state 0x48' we had before we changed the firmware. Do anybody know something about this (are we doing something wrong, or has someone else the same trouble ?), please post or mail it directly to 'muenzel@tat.pysik.uni-tuebingen.de' tanx in advance Stefan "SAM" Muenzel Tel.: 49-7071-296387 Lehr- und Forschungsbereich Telex: 726 2867 UTNA D Theoretische Astrophysik Telefax: 49-7071-295400 Universitaet Tuebingen muenzel@tat.physik.uni-tuebingen.de Auf der Morgenstelle 10 PSI%45050260314::MUENZEL D-7400 Tuebingen West Germany
olson@anchor.esd.sgi.com (Dave Olson) (11/02/90)
In <muenzel.657291850@wega> muenzel@wega.tat.physik.uni-tuebingen.de (Stefan Muenzel) writes: | Once more a problem with the EXA-Byte: | We have a EXA-Byte 8200 and want to use it with a SGI 4D/20. | But when we try to tar some bytes we get messages like the following: | | Oct 22 18:05:04 mira unix: NOTICE: SCSI tape #5 Uncorrectable media error | Oct 22 18:05:04 mira unix: NOTICE: SCSI tape #5 Unrecoverable error | Oct 22 18:05:04 mira unix: NOTICE: SCSI tape #5 had 2215 recoverable Errors | | (Copied from the SYSLOG-file). | This occures after some 100 kbytes. Our first guess was, that we had | bad tapes, but we've tried several new ones from Sony and Exabyte. It | seems not to be a problem of the SCSI-bus. The message indicates that the Exabyte returned a check-condition on a write, then returned 'media error' as the specific error type. The recoverable error message indicates that there were a LOT of errors that were recovered from by retries. If all this happens in 100 Kbytes, then I see several possiblities: 1) your heads need cleaning. Get the dry (not wet) cleaning kit and clean the heads. This can make a big difference. Remember that the heads should be cleaned on a regular basis, and more often when using new tapes, since they tend to shed more coating. 2) Get certified data tapes if 1) doesn't work. In any case, we have been told by Exabyte tech people to avoid Maxell and TDK, (as of a year OK; the situation may have changed since then) and to NOT use MP (metal particle) tapes. Sony tapes seem to work pretty well (which isn't surprising, since they make the Exabyte Data tapes). A number of other brands seem to work OK also. 3) Watch your recovered error rate. I typically see a few hundred for multi-Mb archives. Whatever your rates are, keep an eye on them, and clean the heads when the error rate rises, or if you are trying new tapes, don't use that brand/type if they consistently return higher error rates. The recovered errors are reported on close of the tape if the tape was read or written (or other commands that moved the tape were used). Typically the counter is reset only when the tape is unloaded. -- Dave Olson Life would be so much easier if we could just look at the source code.
mccalpin@perelandra.cms.udel.edu (John D. McCalpin) (11/04/90)
>>>>> On 2 Nov 90 00:34:44 GMT, olson@anchor.esd.sgi.com (Dave Olson) said:
Dave> 1) your heads need cleaning. Get the dry (not wet) cleaning kit and
Dave> clean the heads. This can make a big difference.
Are there any specific brands/types of head cleaner that I should look
for? Any clues as to where I can find them?
Dave> 2) Get certified data tapes if 1) doesn't work. In any case, we
Dave> have been told by Exabyte tech people to avoid Maxell and TDK,
Dave> (as of a year OK; the situation may have changed since then)
Dave> and to NOT use MP (metal particle) tapes. Sony tapes seem to
Dave> work pretty well (which isn't surprising, since they make the
Dave> Exabyte Data tapes). A number of other brands seem to work OK
Dave> also.
Where does one buy these tapes? The only tapes I have *ever* seen are
*all* MP (metal particle) tapes --- with the exception of the one
Exabyte tape that came with the drive. In particular, the Sony tapes
that I have seen advertised (Global computer supplies) are MP tapes....
--
John D. McCalpin mccalpin@perelandra.cms.udel.edu
Assistant Professor mccalpin@vax1.udel.edu
College of Marine Studies, U. Del. J.MCCALPIN/OMNETsrp@babar.mmwb.ucsf.edu (Scott R. Presnell) (11/05/90)
olson@anchor.esd.sgi.com (Dave Olson) writes: >3) Watch your recovered error rate. I typically see a few hundred > for multi-Mb archives. Whatever your rates are, keep an eye on > them, and clean the heads when the error rate rises, or if you > are trying new tapes, don't use that brand/type if they consistently > return higher error rates. > The recovered errors are reported on close of the tape if the > tape was read or written (or other commands that moved the tape > were used). Typically the counter is reset only when the tape > is unloaded. > Dave Olson I *do* see a few hundred recoverable errors per backup. Since day one. Why is the recovered error rate so high? Or at least why is it so much higher per Mb than the 150Mb QIC drives? Media limitations? or does it have something to do with the driver? There is a cluster of suns here that gets backed up with an exabyte, and that drive doesn't seem to report nearly the error rate that I see. (I think we're talking at least 10:1 sun:SGI). (sorry if that had been covered before). - Scott (srp@cgl.ucsf.edu) >Life would be so much easier if we could just look at the source code. -- But what if we could *hack*, recompile, and execute? -- Scott Presnell +1 (415) 476-9890 Pharm. Chem., S-926 Internet: srp@cgl.ucsf.edu University of California UUCP: ...ucbvax!ucsfcgl!srp San Francisco, CA. 94143-0446 Bitnet: srp@ucsfcgl.bitnet
jeff@contex.UUCP (Jeff Carey) (11/06/90)
In article <MCCALPIN.90Nov3111926@pereland.cms.udel.edu>, mccalpin@perelandra.cms.udel.edu (John D. McCalpin) writes: > >>>>> On 2 Nov 90 00:34:44 GMT, olson@anchor.esd.sgi.com (Dave Olson) said: > > Dave> 1) your heads need cleaning. Get the dry (not wet) cleaning kit and > Dave> clean the heads. This can make a big difference. > > Are there any specific brands/types of head cleaner that I should look > for? Any clues as to where I can find them? > > Dave> and to NOT use MP (metal particle) tapes. Sony tapes seem to > > Where does one buy these tapes? The only tapes I have *ever* seen are Here, at Xyvision Design Systems (used to be Contex), we are using, I thought we were told to use, MP tapes. This is wrong? That could be the culprit in some problems we have been having too. At any rate, I, too, would be interested in knowing the answer to John's first question, above. What cleaning kits are recommended and where does one acquire them? Thanks, Jeff -- ------------------------ Jeff Carey contex!jeff@uunet.uu.net
olson@anchor.esd.sgi.com (Dave Olson) (11/11/90)
In <1990Nov2.003444.4650@odin.corp.sgi.com> olson@anchor.esd.sgi.com (Dave Olson) writes: | 1) your heads need cleaning. Get the dry (not wet) cleaning kit and | clean the heads. This can make a big difference. Remember that | the heads should be cleaned on a regular basis, and more often | when using new tapes, since they tend to shed more coating. | | 2) Get certified data tapes if 1) doesn't work. In any case, we | have been told by Exabyte tech people to avoid Maxell and TDK, | (as of a year OK; the situation may have changed since then) | and to NOT use MP (metal particle) tapes. Sony tapes seem to | work pretty well (which isn't surprising, since they make the | Exabyte Data tapes). A number of other brands seem to work OK | also. I got more information about the tape types. It turns out that MP (metal particle) is OK to use, the type to avoid is something called 'high band' or 'super-resolution'; I haven't run across this stuff, since I don't use 8mm video equipment, so I don't know the technical name for it. I'm sorry for the mis-information; I apparently misunderstood the reply last time I asked Exabyte support. Also, the Exabyte support person I talked to still says to avoid Maxell, and recommends (if you aren't going to use Data Grade tapes) the Sony or Fuji brands. Apparently TDK is now in the OK, but not great category. Finally, the cleaning kits seem to still be available only through Exabyte and their distributors (i.e., you won't find it at most computer supply operations). I still haven't found out if SGI carries the cleaning kits; talk to your local SGI sales office if you really need to know. -- Dave Olson Life would be so much easier if we could just look at the source code.