[rhn-users] Gigabit transfer speeds

[Dan Hunter]

I have already set the packet size as large as the windows driver allow - MTU = 7 Kb

But coping from a very high speed disk, or RAM drive is certainly a good question.
Is the limitation the ethernet, PCI bus, hard driver controller, or the hard drive itself????

Hmmm, me thinks an experiment or two is in the wind!
  ----- Original Message ----- 
  From: Tim Schoenfelder 
  To: Red Hat Network Users List 
  Sent: Monday, August 21, 2006 1:37 PM
  Subject: Re: [rhn-users] Gigabit transfer speeds


  Increase your packet size...

  One of our networking class projects a couple years ago was to benchmark gigibit ethernet transfer speeds.  

  I benchmarked 700mb/s+ between two Linux PCs which was reasonable to our instructor. 

  He emphasized that the brand/chipset of cards made a big difference ( it wasn't the most expensive that performed best ... ) as well as the drivers.

  Some of his published tests as described below show that you can achieve at least 700mb/s even with 32bit Netgear GA622T cards as illustrated in a ps link from his website: 

  http://www.cs.uni.edu/~gray/

  Benchmark project links:
  http://www.cs.uni.edu/~gray/gig-over-copper/
  http://www.cs.uni.edu/~gray/gig-over-copper/gig-over-copper.html

  PS file showing performance benchmarks ( note 700mb/s+ requires packet size of 100k+ bytes ): 

  http://www.cs.uni.edu/~gray/gig-over-copper/hsln-lcn.ps

  Tim


  On 8/21/06, Corne Beerse <cbeerse at gmail.com> wrote:
    Dan Hunter wrote:

    > I regularly move large files from a windows XP machine to a Fedora
    > Core 5 machine.
    > To avoid bothering other network users, I purchased two Linksys EG1032
    > gigabit ether net cards. 
    > The cards have been installed.  a direct PC to PC gigabit cross over
    > cable connects them.
    > A separate set of IP address have been set up.
    > I can verify that data is being transfered over the gigabit cable with 
    > windows task manager.
    >
    > Transfers over the 10/100 link show up at 82 or 83 percent - about 80
    > Mbps.
    > Transfers over the gigabit link show up at 20 to 26 percent - about
    > 230 Mbps. 
    >
    > What do I have set up wrong?
    >
    >
    Your expectations are to high. If you have about 20% utilisation with a
    Gbit nic, I'd say you are doing verry nice.

    With the move to gigabit networking, the nic is no longer the 
    bottleneck. If you move data from disk on one machine or to disk on an
    other, the disk-controllers, disk interfaces or even the actual disks
    are most likely the bottlenecks. Then, the disk does not need to be the 
    bottleneck. Think about the speed of internal busses and for which they
    are used while you are dumping data...


    CBee

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  -- 
  Tim Schoenfelder
  http://timschoenfelder.com 


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