[Beowulf] Migrating from IB datagram mode to connected mode live ?

Håkon Bugge h-bugge at online.no
Thu Apr 19 02:06:06 PDT 2012

On 19. apr. 2012, at 10.10, Chris Samuel wrote:

> On Thursday 19 April 2012 17:04:53 Håkon Bugge wrote:
>> echo connected >  /sys/class/net/ib0/mode
> Umm, yes, we know how to set it; the question is whether introducing 
> nodes that have it set onto an IB fabric with nodes in datagram mode 
> will cause issues and/or instability ?
> For instance can nodes in connected mode talk to nodes in datagram 
> mode, and vice versa ?

Datagram mode is required. For connected mode, the node is required to establish both an UD QP (for nodes not capable of connected mode and multicast) and an RC QP. During address resolution, the requester capability is included as part of the L2 address.

So yes, it works.


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