[Beowulf] Cluster Networking

Skylar Thompson skylar at cs.earlham.edu
Fri Jun 26 11:03:01 PDT 2009

Dmitry Zaletnev wrote:
> Hi, I have two questions:
> 1. Is there any influence on performance of a NFS-server from the usage of x32 CPU and OS instead of x64, if all other characteristics of the system, i.e. amount of RAM, soft-SATA-II RAID 0, Realtek GLAN NIC are the same?

If you run 32-bit, make sure you have PAE enabled if you have more than
4GB of RAM. You'll still get some overhead when accessing more than 4GB
of cache, since the kernel will have to swap out page tables for each
4GB chunk of physical RAM. A 64-bit kernel would be able to address all
the RAM you have without having to resort to page table trickery.

> 2. Is the Etherchannel technology (channel bonding) useful for CFD-application running on a cluster of two Dual-Xeon servers?

There's a variety of different ways to do channel bonding. I would read
up on and experiemnt with all of them and choose one that ensures that
you actually balance across all the NICs in your systems. It sounds like
you have a small cluster, which means that using the MAC address for the
hash is likely going to cause both your cluster systems to hash to the
same NIC, so you won't get any balancing at all. On Linux, you can also
use a combination of MAC and IP, or IP and port, which will likely be
better at balancing the load.

-- Skylar Thompson (skylar at cs.earlham.edu)
-- http://www.cs.earlham.edu/~skylar/

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