On Wed, Jan 18, 2012 at 6:46 PM, Roland Dreier [off-list ref] wrote:

quoted

Why would you crash is you have device mapper multipath configured to handle
path fail over? We have tons of enterprise customers that use that...

cf http://www.spinics.net/lists/linux-scsi/msg56254.html

Basically hot unplug of an sdX can oops on any recent kernel, no
matter what dm stuff you have on top.

quoted

On the broader topic of error handling and so on, I do agree that is always
an area of concern (how many times to retry, how long time outs need to be,
when to panic/reboot or propagate up an error code)

Yes, especially the scsi eh stuff escalating to a host reset when
a single drive has gone bad -- even if the HBA is happily doing IO
to other drives, we'll kill access to the whole SAS fabric.

With which SCSI low-level diver does that occur and how does the call
stack look like ? I haven't encountered any such issues while testing
the srp-ha patch set. However, I have to admit that the issues
mentioned in the description of commit 3308511 were discovered while
testing the srp-ha patch set.

Bart.