Date: Sun, 26 Jan 2014 15:46:06 -0700 From: "Justin T. Gibbs" <gibbs@scsiguy.com> To: Ben Laurie <ben@links.org> Cc: freebsd-scsi@freebsd.org Subject: Re: Dropped interrupts Message-ID: <888F991A-96C7-48C0-AAC6-0D432BD78A46@scsiguy.com> In-Reply-To: <CAG5KPzwvBoBvh210Vn5GG6eBVNXKWCkuh6J_FLGao0L6aPAmcw@mail.gmail.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>
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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: >>=20 >>> Aha, finally got the error again=85 >>=20 >> I don=92t 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. >=20 > 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. >=20 >> 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). >>=20 >> 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? >=20 > No idea, its a very old LTO-2 drive. I'll see if I can find an update. >=20 >> How many write cycles do you have on your media? >=20 > I have seen this error on brand new media. I'd guess the most cycles > any tape has had is around 10. >=20 >> When was the last time you cleaned the drive? >=20 > 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=92t make them unnecessary. Certain LTO drives will tell you = (e.g. light a LED) when they require cleaning, but I don=92t 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. =97 Justin=
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