[Beowulf] Channel bonding, again

[Henning Fehrmann]

Hallo Jan,

> That is not 100% correct. There are at least 6 mod that the bonding
> device of linux supports. balance-alb and balance-tlb are not
> assigning the same MAC to the interfaces in the bond. Therefore you
> don't need a switch that supports trunks or something similar.
Hmm, we tried balance-tlb. After view seconds either the bonding device was down
with a bunch of kernel logs or the node hang-up.
Maybe, somebody can report on this problem.

> 
> The problem ist that the performance of the bonding device under linux
> is far away from being optimal (as far as i saw). The round-robin or
> ad modes do not bring more than 140 to 150 MB/s out of 2 Gigabit
> links.

> The load balancing modi allow multiple connections to be fast but are
> not speeding up a single connection (each connection is limited to the
> speed of a single link in the bond). 

Exactly.

Using the VLAN trick the student reported a transmission rate of 240MB/s 
using round-robin, NFS (reading from a ram-disk) and 2 Gigabit links,
also, if one establishes a single connection.
We don't know yet, how it scales in a cluster. There might be a problem
with reordering the packages.

Regards 
Henning