Re: rsockets addressing

[Yann Droneaud <ydroneaud-RlY5vtjFyJ3QT0dZR+AlfA@public.gmane.org>]

Hi,

Le lundi 16 septembre 2013 à 18:31 +0200, Gandalf Corvotempesta a
écrit :
> 2013/9/16 Yann Droneaud <ydroneaud-RlY5vtjFyJ3QT0dZR+AlfA@public.gmane.org>:
> > You have to use InfiniBand port bonding to benefit from fail-over (through
> > APM: Automatic Path Migration ?)
> >
> > http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/networking/bonding.txt
> 
> IB boinding is exactly what I would like to do but I have some questions:
> 
> 1. is the ISL supported? I've seen that is not suggested to
> interconnect two IB switches (and I don't know why)
> http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/networking/bonding.txt#n1967
> Without ISL and using two different IB switches, one port failure will
> result in the whole node down because there is no other active path to
> the primary switch
> This would be good in my environment by I prefere to get a real failover.
> 

The InfiniBand fabrics support "ISL" ... indeed.

InfiniBand fabrics support more complicated network topology than
(plain) Ethernet: that's why there's (at least) one Subnet Manager,
while Ethernet struggle with Spanning Tree ...

You definitely need link between switches if you want to use a "high
availability" fabric topology with HCA ports connected to differents
switches. (additionally, a switch should have a link to two others
switches ... then it's starting to be complicated, since you have to
design your fabric topology to match the communication pattern / data
locality used by your application ...).

> 2. can I use active-active mode like standard ethernet bonding with
> some sort of balancing?
> http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/networking/bonding.txt#n2127

AFAIK, IPoIB bonding doesn't support "active-active" bonding.
Only high availability is provided. Link aggregate is not supported.

Regards.

-- 
Yann Droneaud
OPTEYA


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