Dropped interrupts

[Ben Laurie]

On 31 January 2014 17:32, Ben Laurie <ben at links.org> wrote:
> 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.

There does seem to be a firmware upgrade, though.
http://www.dell.com/support/drivers/us/en/19/DriverDetails/Product/powervault-lto2-110t?driverId=H29Y4&osCode=WNET&fileId=2731097569&languageCode=en&categoryId=TH#OldVersion.

But ... dunno how to install it. The Linux tools don't work under
FreeBSD, it seems.