Re: SCSI tape [more info]
From: Robert Nichols (rnichols42_at_comcast.net)
Date: 04/30/05
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- In reply to: T. Horsnell: "Re: SCSI tape [more info]"
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To: fedora-list@redhat.com Date: Fri, 29 Apr 2005 18:26:35 -0500
T. Horsnell wrote:
> I found A PC running FC3 (kernel 2.6.10-1.741_FC3) which had
> an Adaptec 29160 SCSI adapter in a 32-bit PCI slot.
> I connected my SDLT2 library to it and repeated my tests.
> Everything worked!.
>
> Adaptec 39320 uses aic79xx driver
> Adaptec 29160 uses aic7xxx driver
>
> I took the 29160 out of the PC, intalled it in the Opteron
> box (into a 64-bit PCI-X slot) and repeated the tests. Failure.
> The Opteron has 4 kernels available:
> 2.6.10-1.770_FC3smp
> 2.6.10-1.770_FC3smp
> 2.6.10-1.770_FC3
> 2.6.10-1.770_FC3
> I tried them all. Failure.
> I even booted from a Knoppix CD with 2.4.27.
> (This presumably means I'm running a 32-bit kernel on a 64-bit box). Failure.
>
> I remembered I had a desktop Compaq SDLT1 tapedrive on one of my systems.
> I tried that on the 29160 adapter. Success.
> I tried it on the 39320 adapter. Success.
> Is it some sort of datarate problem I ask myself (the
> SDLT1 is about half the speed of the SDL2) and the SDLT2
> worked on the PC.
> I moved the 2960 out of the PCI-X slot into a PCI slot
> and tried again with the 5 Kernels listed above. Failure.
>
> I'm now running out of ideas/energy/hardware.
> With my original configuration, (Opteron, 2.6.10-1.770_FC3smp,
> Adaptec 39320, dual SDLT2) I can get verified tar dumps
> of at least 4GB (I havent tried anything bigger) provided I
> use a record size > 32768 (64*512). 65536 (256*512) works fine,
> as does 131072 (256*512). 32768 fails.
>
> Is it time to file a bug report? Who with?
>
> Thanks for any and all suggestions,
This is sounding a lot like a problem I ran into with a DDS-2 tape
drive (Archive IBM4326NP/RP). When the drive's internal counter of
bytes written to the tape (compressed data) reached 4 GiB the drive
would (a) skip writing one block of data, and (b) fail to log any
further errors (e.g., write retries). The byte counter would remain
stuck at the 4 GiB mark. No error was ever reported by the drive.
This was using an Adaptec 2940 SCSI adapter and the aic7xxx driver.
I'm reasonably sure that neither the SCSI adapter nor the driver was
at fault because they see only the uncompressed data stream and have
no way to know when the drive's internal counter hits 4 GiB. In
addition, the same adapter and driver work just fine on a DDS-3 tape
drive.
I first realized there was a problem when I noticed that the drive's
block counter (shown by "mt tell") sometimes incremented by one less
than the number of blocks reported by 'dd'. After much testing and
looking at the counters reported by "smartctl -l error" I was able
to identify the problem. Though the advertised capacity of a DDS-2
tape is 4 GB compressed, the counters do not get reset when changing
tapes, so it's possible to encounter the error at any point on the
tape.
-- Bob Nichols rnichols42@comcast.net -- fedora-list mailing list fedora-list@redhat.com To unsubscribe: http://www.redhat.com/mailman/listinfo/fedora-list
- Previous message: Diego Ruiz: "Problem with USB Pen Drive"
- In reply to: T. Horsnell: "Re: SCSI tape [more info]"
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