Re: mpt2sas + raid10 goes boom

[Matthias Prager <linux@matthiasprager.de>]

Thanks for your insights Baruch.
The crc count did not increase any further - so this was probably just
small oddity (was zero before when the write-same issue already
happened). The real issue however does persist. I found a way to
reliably trigger the log messages. Using a program called checksum over
a photo share (which does a lot of reads and one write per file). With
that in place I switched to the 3.4.38 kernel, with which I'm unable to
trigger the problem. I will leave the system at that for now, and try to
reproduce it on my testing machine to see, whether
  c8dc9c6 md: raid1,10: Handle REQ_WRITE_SAME flag in write bios
works for me.

If c8dc9c6 does the trick, it would still be interesting to know why and
how this triggered i/o errors, the strange log message from lsi and
'Resets Between Cmd Acceptance and Completion' as one of the drives
says. Would that mean the driver/firmware from lsi is issuing or passing
on commands to the drive which it does not understand or can't process?

---
Matthias