On Mon, 9 Jun 2003, Eric Siegerman wrote: > Well, "SCSI parity error" seems pretty clear -- data being > received with bad parity by one of your SCSI devices (either the > tape drive or the SCSI adapter; I'm being carefully agnostic as > to which way the data's flowing when the errors are detected). > Most likely the corruption is occurring on the SCSI bus. The > only other possibility I can think of is a firmware bug or other > malfunction in one of the two devices.
seems reasonable. > > can you think of any other non-amanda test i can do that will exercise > > the tape drive as amanda does? > > Only what I've already suggested -- use real disk files instead > of /dev/urandom as your data source. Based on what I'm about to > say, it'd be wise to make sure those files come from the same > drive your Amanda holding disk is on. To get as close as > possible to what Amanda's doing, use the holding-disk files > themselves. ok, i did this (made a big disc file from /dev/urandom, then dd'ed that to the tape), and it still works fine. i emphasise that my discs aren't on the same SCSI bus as the tape drive - the tape drive has its own controller, which no other device uses - but still no errors came. i dd'ed around 2GB of data to the tape, and had no problems at all. > If, as I suspect, the problem is noise on the SCSI bus, one ugly > possibility is that your SCSI cable is picking up noise from the > rest of the system; for example, from the IDE cable that your > disk is connected to. No disk I/O => no noise being transmitted > => no SCSI errors. hopefully, this test has disproved that theory. > The obvious first stab at an answer would be to just move the > cables around inside the case, hoping to get the SCSI cable far > enough away from the noise source. But *please* figure out how > to duplicate the problem first, otherwise you'll never know if > you fixed it! at the moment, duplicating it is *really* easy. any time the amanda taper tries to write to the tape, nothing works (write errors in the first gigabyte). the rest of the time, i can send data to the tape just fine. > A better solution (if this is indeed the problem!) would be > better-quality SCSI cables. so noted. > This is the sort of problem I *hate*! Best of luck with it. <grin> thanks for your ideas! does anyone else have any suggestions, at all, for a tape drive which seems to be fine until amanda uses it, and which then goes south fairly rapidly? does anyone know anything about decoding kernel SCSI error messages? -- Tom Yates - [EMAIL PROTECTED] - http://www.teaparty.net
