Dropped interrupts

[Ben Laurie]

On 31 January 2014 00:44, Justin T. Gibbs <gibbs at scsiguy.com> wrote:
> On Jan 30, 2014, at 3:21 PM, Ben Laurie <ben at links.org> wrote:
>
> On 26 January 2014 22:46, Justin T. Gibbs <gibbs at scsiguy.com> wrote:
>
> On Jan 26, 2014, at 1:52 AM, Ben Laurie <ben at links.org> wrote:
>
> On 25 January 2014 17:15, Justin T. Gibbs <gibbs at scsiguy.com> wrote:
>
> On Jan 24, 2014, at 10:44 PM, Ben Laurie <ben at 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.