Unexpected issues with 2 NVME initiators using the same target

[shahar.salzman]

Hi,

Sorry for the delay, I have been OOO for the past few days.

Indeed the underlying transport is Ethernet, and we have found that flow 
control is disabled on the switch side.
I still do not have access to the system for re-tests with the flow 
control, and 4.10. But I am working on assembling another system.

A little off-topic, but something that may help me get the other system 
up faster, can I use a dual CX4 card as initiator and target (i.e. one 
port going up to the switch, and the other coming back into the system) 
without the kernel looping back? I have a spare CX4, so if possible, I 
will use it to build a mini system for recreates of this sort.

Thanks,
Shahar


On 03/07/2017 03:41 PM, Sagi Grimberg wrote:
>
>> Hi,
>>
>> Shahar/Joseph, what is your link layer conf (IB/Eth) ?
>> In eth case, have you configured some PFC ? if not, can you try it ?
>> I suspect that this is the root cause
>
> The root cause is that the device fails frwr in retransmission
> flow, if PFC is not on, it will happen almost immediately, if not
> it will happen at some point...
>
>> and it might help you avoiding
>> this case, meanwhile we're looking for for the best solution.
>>
>> Adding Vladimir that will run iSER on his performance setup with the new
>> fencing patch (not an NVMEoF related issue).
>> We can run also NVMEoF later on if needed.
>
> Thanks.