Bug#740701: multipath-tools: mkfs fails "Add. Sense: Incompatible medium installed"

[Martin George]

On 6/20/2014 4:36 AM, Hans van Kranenburg wrote:
>
> I really want to understand what this message means and who generated
> it. If I assume it's the NetApp filer that returns this data when
> issuing an UNMAP command, I wonder why. Could any of you NetApp folks
> shed some light on when and how ontap 8.1.2 7-Mode might ever send this
> error back? This could help finding a test case which will trigger this
> error, and to find out why it does not occur in a different situation
> that seems to be identical.
>
> The whole error still does not make a huge amount of sense to me. Why
> would my NetApp system return an error which I only would expect to see
> when using a CD-ROM drive or some USB removable device? It's not like
> all disks suddenly vanished from my FAS and disk shelves, like ejecting
> a CD drive. :-)
>
> [1] http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=740701
>

So firstly, the question arises why your kernel marked all paths as 
failed when you hit this error. This actually resembles the old Linux 
behavior where for a device error such as a MEDIUM ERROR, it gets 
retried on all paths available to the LUN, all which result in the same 
error, and hence all paths get marked as failed. This was addressed with 
the upstream patch at 
http://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/commit/?id=63583cca745f440167bf27877182dc13e19d4bcf, 
where more fine-grained error handling is now available. With this, 
device errors such as MEDIUM ERROR are no longer retried since it treats 
such errors as permanent errors. That makes me suspect your kernel is 
already missing some of the key patches from the upstream kernel in 
context with this error handling. And given that UNMAP has also been a 
relatively new feature which underwent several upstream revisions to get 
to the current stable state, it would be prudent for you to check if 
your kernel is up-to-date with its SCSI & UNMAP handling.

That said, it is indeed strange that you hit a MEDIUM ERROR in the first 
place, when using UNMAP. As described above, that's a device error. So 
does this fail even for other commands such as a regular write (you 
could try this with dd) or even a simple TUR command (like say using 
sg_turs -v /dev/mpathX)?

-Martin