Re: v3.15 dm-mpath regression: cable pull test causes I/O hang

[Bart Van Assche <bvanassche@acm.org>]

On 07/03/14 16:05, Mike Snitzer wrote:
> How easy would it be to replicate your testbed?  Is it uniquely FIO hw
> dependent?  How are you simulating the cable pull tests?
> 
> I'd love to setup a testbed that would enable me to chase this more
> interactively rather than punting to you for testing.

Hello Mike,

The only nonstandard hardware that is required to run my test is a pair
of InfiniBand HCA's and an IB cable to connect these back-to-back. The
test I ran is as follows:
* Let an SRP initiator log in to an SRP target system.
* Start multipathd and srpd.
* Start a fio data integrity test on the initiator system on top of
  /dev/dm-0.
* From the target system simulate a cable pull by disabling IB traffic
  via the ibportstate command.
* After a random delay, unload and reload SCST and the IB stack. This
  makes the IB ports operational again.
* After a random delay, repeat the previous two steps.

If you want I can send you the scripts I use to run this test and also
the instructions that are necessary to build and install the SCST SRP
target driver.

Bart.