Single, dual or quad Gigabit?

Jerker Nyberg jerker at Update.UU.SE
Wed May 26 05:12:01 CDT 2004


On Wed, 26 May 2004, Mark Watts wrote:

> PCI-X only has so much bandwidth (I forget exactly how much). If you
> stuff too many nic's in there, you'll hit that limit and physically not
> be able to go any faster. a Quad card would certainly be too much.

PCI-X (64bit at 133MHz) is in theory 1064 MByte/s. Quad full duplex gigabit
ethernet is in theory 1000 MByte/s. And as long as you mostly are
interested in half duplex (a NFS-server with mostly reads) the bus should
be good enough... Getting data from the disks and memory bandwidth on the
server might be a limiting factor. I guess one shouldn't put the disk
controllers on the same PCI-X-bus as the ethernet adaptors.

Here is an interesting example of running off-the-shelf Dell Poweredge
2650 servers with 10 Gbig/s ethernet over half the world getting speeds up
to 4226 Mbit/s (528 MByte/s).

"SUNET Internet2 Land Speed Record: 69.073 Pbmps"
http://proj.sunet.se/LSR2/

Regards,
Jerker Nyberg.
Uppsala Sweden.




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