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Subject: [OMPI users] subnet specification for MPI when multiple networks are present
From: Rahul Nabar (rpnabar_at_[hidden])
Date: 2010-06-22 16:43:41


I have compute-nodes with twin eth interfaces 1GigE and 10GigE. In the
OpenMPI docs I found an instruction:

" It is therefore very important that if active ports on the same host
are on physically separate fabrics, they must have different subnet
IDs."

Is this the same "subnet" that is set via an ifconfig e.g. 192.168.x.x
or 10.0.x.x that I have for my 10Gig and 1Gig networks? Or is this a
different usage of the term "subnet"?

The reason I am confused is that it subsequently discusses setting the
right subnets by using the subnet-managers "opensm" or "Cisco High
Performance Subnet Manager". I don't seem to have either of these on
my system but I have set the subnets via the usual eth and ifcfg
framework. Is that sufficient?

[I am using Chelsio 10GigE cards with the OpenIB framework]

-- 
Rahul