Autochanger Not Recognized (again)

[Scott Buckingham]

I've had to replace our C6367A, DDS-3 autochanging tape unit again on our HP-UX 11, K-360 machine. As with the last time, I cannot communicate with it now that it is installed. The results of an 'ioscan -fnC tape' are attached and it shows that everything is CLAIMED. However, when i try to fbackup to /de/rmt/3m, I receive "output file /dev/rmt/3m encountered an I/O error" message. The machine was rebooted yesterday in hopes that would straighten things out but to no avail. The SCSI ID on the unit is 4 and it looks to be a match. Did I receive a bad unit from the vendor or is there something else I need to do?

Thank you.

[Mark Grant]

Do you receive this error immediately or after some random time. If the latter, I would start looking at scsi resets.

[Scott Buckingham]

It's immediate.

[Mark Grant]

I could be the tape.

Other that, if you are there are no SCSI ID conflicts then I would get the engineer back

[A. Clay Stephenson]

The first thing that I would do is install the latest cumulative tape driver patch, PHKL_29247. Since you mention this is a recurring problem, I would begin to suspect other components (controller, cabling, terminators, terminator power supplied by at least one device on the bus, SCSI ID conflict. I assume you are using one of the SE HP-PB SE-SCSI controllers (28655A); if so, the tape2 driver is appropriate.

[Scott Buckingham]

I should clarify what I meant by "again". This is the second tape unit that has gone bad on us within the past year. I had trouble on the last unit getting it to play nicely with fbackup, tar, Omniback, etc. because the SCSI ID changed (and I didn't know what I was doing). However, this time around, things seem to check out as far as ioscan is concerned. I'm not a hardware guy by any means, but based on my past experience I would expect the drive to work as it is set right now. Could it be something other than the drive itself? If ioscan can find the device and claim it, I would think that anything other than the drive itself would be OK. Is this correct thinking?

[A. Clay Stephenson]

Unfortunately Scott, this is not correct thinking. For example, a non-terminated (or poorly terminated) SCSI bus will, in most cases, work almost perfectly --- the very worst kind of problem to have. You will see similar problems if you exceed (or even approach) maximum SCSI bus lengths. For you, that is 6m. That is a TOTAL length including internal and external connections --- not just the length of external cable. B ad controllers can cause silimar problems. If no device is supplying termination power, you can also have very flakey problems. If you can connect another device on this same bus and it behaves normally (more than simply an ioscan) then I think you can safely assume that your replacement tape drive is at fault.


I would certainly apply the patch I mentioned.

[Scott Buckingham]

Oh boy, then I guess I'm in trouble! We no longer have a support agreement with HP so I guess I'll have to find a 3rd party to come in and check things out. As far as applying the patch, I see it has several dependency patches as well. I have not applied HP patches before, does this mean they all need to be applied or are they already included?

[A. Clay Stephenson]

Run swlist to see if the dependent patches have already been installed -- or indeed if the cumulative tape driver patch has already been installed.

The easist method to install the patches is to copy all the dependencies and patches to a depot and install them as a unit. Under SAM, Software management there is an option to copy to depot. Use that to copy each patch to a depot. Next start swinstall (just type swinstall) and select your new depot as the source. You then "Mark" each patch and Install in one session.

You can also install the dependencies one at a time using swinstall but those may require a rebbot between each one.

[Scott Buckingham]

Thanks, Clay, for the information. I'll have to plan the patch process as this is our production database server. If this doesn't get my tape drive working, then you think it'll be best for me to get someone in here to troubleshoot the problem?