Gigabit: How long should this transfer take?

December 12, 2009 at 05:52:24
Specs: CentOS 5.4 64-bit, Atom 330 1.6Ghz Dual Core/2GB of RAM
How long do you think it should take to transfer a near 5GB ISO across a 
gigabit LAN?

I replaced an old Rackable Systems™ 2x dual core Opteron server with a low 
power SuperMicro rackmount server (with an Atom 330 dual-core processor, 
2GB of RAM).

Both have gigabit ethernet, and "ethtool eth0" shows that the SuperMicro is 
indeed at 1000/Full, but for some reason it only transfers that file at roughly 
half the speed of what I thought I saw on the Opteron Box (13MB/s compared 
to 30MB/s).

It's not a deal-breaker to me, but is this a limitation of the processor? 

OS: CentOS 5.4 (x86_64)
Switch: HP ProCurve Gigabit

Thanks in advance.

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December 12, 2009 at 07:12:11
There are so many "it depends" that it is impossible to say.

The speed of each CPU, the hard disk speed, what other tasks each computer is performing at the time, all play a part. The LAN doesn't operate in isolation from the rest of the system.

When you are measuring data transfer speeds you should be using bits not bytes. Bytes doesn't take into consideration of the overheads that are needed which can be as much as 10% of all the data transfered.


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December 12, 2009 at 09:52:28
Good to know, thanks.

It's a fresh build, with nothing running at the moment.

Do you think installing a separate NIC would help at all (the
current two are onboard)? It would be a standard Intel desktop


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December 12, 2009 at 15:46:39
About the only way to help would be to install a server grade nic. They offload a lot of cpu from the host. You are running into backplane and cpu issues that may not be overcome.

The opteron would have been made for serving and my guess a higher end product. The atom is the bargain basement model.

I'd expect the opteron to have pci-x channel maybe. Much faster than pci

Playing to the angels
Les Paul (1915-2009)

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Related Solutions

December 13, 2009 at 11:42:36
there's a pci-express (x8) expansion slot. If I don't need it for
anything else, I'll put in a server grade NIC. The Opteron was
overkill for what the it was being used for, hence, the
downgrade. I may put in a SSD as well.


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