Date: Fri, 31 Jan 2014 17:32:02 +0000 From: Ben Laurie <ben@links.org> To: "Justin T. Gibbs" <gibbs@scsiguy.com> Cc: freebsd-scsi@freebsd.org Subject: Re: Dropped interrupts Message-ID: <CAG5KPzycrD%2BKyOi%2B9Gvh=n5SkKCXT0xEnBGXVMmBptVhqx03vQ@mail.gmail.com> In-Reply-To: <80532F4C-9206-4268-936E-66F352087052@scsiguy.com> References: <CAG5KPzxUAnORPSyJDrSdBBNE7MBi-dD=M6=E1rMG%2Bc8rn4deUQ@mail.gmail.com> <AE41EB93-26BD-4BD0-9913-7CD0A5B6E1A4@scsiguy.com> <CAG5KPzwR5=WNKc5hck8F7CtCtk3mivwYFRFeCJT_zWdnetW=3w@mail.gmail.com> <84D23688-DDC6-421E-9D21-3DA646229038@scsiguy.com> <CAG5KPzxqxmzfnAiUyVyApMs5XqKpH0F0sbTxy1h=4cL=rEROpQ@mail.gmail.com> <CAG5KPzyPXLEOAFKTAW%2BJaai=XbT3mi5yGHs1LnUbMcD-LfQ1YQ@mail.gmail.com> <CAG5KPzzVpvH=miguqKnO0pA2jmWm-_7s7W-Nbh%2BVeHKv7x7ikw@mail.gmail.com> <8680A21D-78D7-4B65-A502-17F0C3B70291@scsiguy.com> <CAG5KPzwvBoBvh210Vn5GG6eBVNXKWCkuh6J_FLGao0L6aPAmcw@mail.gmail.com> <888F991A-96C7-48C0-AAC6-0D432BD78A46@scsiguy.com> <CAG5KPzzrenHbYSBY5zQ1GNKg%2BT2nY0aAKp3uGSw=Rxn1=KYnow@mail.gmail.com> <80532F4C-9206-4268-936E-66F352087052@scsiguy.com>
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On 31 January 2014 00:44, Justin T. Gibbs <gibbs@scsiguy.com> wrote: > On Jan 30, 2014, at 3:21 PM, Ben Laurie <ben@links.org> wrote: > > On 26 January 2014 22:46, Justin T. Gibbs <gibbs@scsiguy.com> wrote: > > On Jan 26, 2014, at 1:52 AM, Ben Laurie <ben@links.org> wrote: > > On 25 January 2014 17:15, Justin T. Gibbs <gibbs@scsiguy.com> wrote: > > On Jan 24, 2014, at 10:44 PM, Ben Laurie <ben@links.org> wrote: > > Aha, finally got the error again... > > > I don't know enough about your backup or Bacula to know if this is amount > that should be written, but we attempted a write in variable block mode of > 64512 bytes. > > > I don;t think there's anything wrong with that. Not at the machine > right now, but I think that's actually the default max block. No idea > why. > > The command, data transfer list, and controller state are all consistent > with this. The command was successfully transferred to the tape drive, but > it never transitioned to data phase to allow us to begin the data transfer. > (In parallel SCSI, the target controls all state transitions). > > Since there are no parity errors or other indications of a transport error, > my hunch is that this is a tape drive issue. Are you running the latest > available firmware for it? > > > No idea, its a very old LTO-2 drive. I'll see if I can find an update. > > How many write cycles do you have on your media? > > > I have seen this error on brand new media. I'd guess the most cycles > any tape has had is around 10. > > When was the last time you cleaned the drive? > > > LTO drives are self-cleaning. So ... never. > > > This is a popular misconception. LTO drives include brushes deployed during > load or unload to remove large particle contamination off the head. This > increases the time interval between traditional cleanings, but doesn't make > them unnecessary. Certain LTO drives will tell you (e.g. light a LED) when > they require cleaning, but I don't know if this is one of them. There have > also been firmware bugs on some drives that prevent the cleaning indicator > from working as expected. > > If the drive has over 500 hours on it, I would suggest a cleaning pass. Probably has. I don't have a cleaning tape, though. > Are you suggesting that a need for cleaning could cause this problem? > > > I can't say why the drive isn't responding. But if it hasn't been cleaned > since it was manufactured, you are probably getting less data per tape than > optimal, slower transfer speeds than optimal, or both. > > I don't know if the LTO-2 model listed on this page is the same as what you > have, but if it is, there were several firmware releases after 3AYC: > > http://www-01.ibm.com/support/docview.wss?uid=ssg1S4000055 The install instructions (http://www-01.ibm.com/support/docview.wss?uid=ssg1S7000704&aid=1) make no sense in the context of my drive, so I guess not.
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