[openib-general] [openfabrics-ewg] OFED 1.1 release - schedule and features

[Vladimir Sokolovsky]

Hi Or,
See below,

Regards,
Vladimir

Or Gerlitz wrote:
> Vladimir Sokolovsky wrote:
>> Hi Or,
>> I am working on IPoIB failover.
>> I tried Michael's Tsirkin patch for ipoib (updating neighbor 
>> structure) and it fixes the issue Roland was talking about.
>>
>> Meanwhile I have tested the following flow:
>> /*_Setup description:_*/
>>
>>    host1 - 2 IB ports connected to IB switch.
>>            ib0: 11.0.0.1
>>            ib1: 12.0.0.1
>>
>>    host2 - port 1 connected to the IB switch.
>>            ib0: 11.0.0.2
>>            opensm over port1
>>
>>
>> /*_Flow description:_*/
>>    - ping host2 -> 11.0.0.1 (passed)
>>    - set port1 of the host1 to 'DOWN' state (disconnect the port from 
>> IB subnet)
>>    - ping host2 -> 11.0.0.1 (failed)
>>    - ifconfig ib0 0.0.0.0 (on host1)
>>    - ifconfig ib1 11.0.0.1 (on host1)
>>    - arping -I ib1 11.0.0.1 (on host1)
>>    - ping host2 -> 11.0.0.1 (passed)
>>
>> arping in this case was not really necessary because ping issues ARP 
>> requests by himself.
>
> Hi Vlad,
>
> Did you have any special reason to assign host1:ib1 an IP address 
> ***before*** the failover? is the reason for that happen to be having 
> it joins the IPv4 multicast group at "batch time", that is not during 
> the failover?
ib1 interface is loaded in any case (with or without configuration) if 
ib0 is loaded by /etc/init.d/network or /etc/init.d/openibd. It can't be 
configured with IP 0.0.0.0 - it fails to start with this configuration.
So, I gave it some IP in a different IP subnet.
>
> >    - arping -I ib1 11.0.0.1 (on host1)
>
> -U  Unsolicited ARP mode to update neighbours' ARP caches. No replies 
> are expected
>
> -A  The same as -U, but ARP REPLY packets used instead of ARP REQUEST.
>
> I think we want arping to send a gratuitous arp with the MAC of ib1
> so weren't you need to provide the -U or -A command line to arping?
>
You are right I used 'arping -A ...' (fogot to insert it in the email). 
Actually, I have added my flag '-R' which means '-A over IPoIB'
> If i understand correct, gratuitous arp was not sent in your usage 
> case so i am not sure Michael's patch was exercised.
>
> > Note: I updated the original arping to be able to send broadcast using
> > ipv4_bcast_addr.
>
> Can you please send the patch to arping?
>
Attached (arping_full_ib.c - arping.c with changes for IPoIB).
> > Also, I have tested ssh over IPoIB with the same flow. In this case
> > arping also wasn't necessary , but it makes an update of neighbors
> > with the new MAC address (of ib1 interface) more quickly.
>
> Two interesting test cases you might want to validate your approach 
> with is something "long" ie that delivers much traffic before and 
> after the failover ie: iperf or netperf over TCP AND UDP. I have not 
> validated it but i think UDP would not generate ARP so the gratuitous 
> is the only way   to update the remote system with the MAC change.
>
I will test it later.
> Or.
>
>

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