[Beowulf] Gigabit switch recommendations (again)

[Joe Landman]

stephen mulcahy wrote:

> 
> What I'm seeing in my research is that there are a bunch of switches 
> around the €600 mark (such as D-Link's DGS-1248T) and then a bunch of 
> switches around the €1300 mark (such as HP's Procurve 2810-48G). If you 

A customer recently replaced the D-Link model switch with a larger 
Procurve backplane unit.  They had many issues with file system fall out 
(NFS ... don't know why, it is supposed to handle this correctly), and 
broken MPI sockets on the D-Link.  All their problems went away after 
the procurve was installed (no I am not a shill/sales person for HP, and 
I don't own any HP stock).


> want to spend more, there are plenty of options above and beyond also. 
> What I can't see is a clear difference between the €600 switches and the 
> €1300 switches on the performance side.
> 
> Has anyone any direct experience of switches in these different price 
> ranges and has anyone seen significant performance differences? Or do 
> the low prices simply reflect the competition and the increasingly 
> commodity nature of gigabit switches?

Yeah ... the lower end switches usually don't talk about their backplane 
bandwidth, for good reason.  A fair number of the lower end switches 
will happily toss packets under load.  Fine for desktop users, not so 
fine for clusters.

This said, we have had good luck with a few lower end switches.  I still 
see people on various lists (Rocks and others) complain about various 
Dell (rebranded SMC) and other models.  Turns out there is some 
config-foo you have to do to make them intelligent for clusters.


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Joseph Landman, Ph.D
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