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Re: [K12OSN] More feedback on Fedora 10 + LTSP



David Hopkins wrote:

ethtool reports that the link is up and 1000Mb, full duplex. (mii-tool
says it is 100Mbit but that tool is quite old). dmesg also shows the
link up at 1000Mb as well.

Is the switch managed so you can check there as well? You should see no errors in the server 'ifconfig' output or the switch interface statistics (or at most a couple if you have replugged the connections). If the switch isn't managed, it might have a link light indicator that shows full/half duplex.

Now, I tested the throughput between the server and the file server
using netio.  This reports that I have a sustained throughput of
114MB/sec (or about appr 900Mbit/sec) between my servers on the
network.  Since I am using the same NIC and switches for the thin
client side, I would expect about the same performance.

Are you testing this with an equal number of concurrent connections as where you see tuxtype/math performance fall - and across the same switch connections? Often a duplex mismatch or similar error degrades badly with concurrent operations but might not show up with a single connection test.

I then reverted back to the original server, and noticed the same
performance issue. I swapped out cables but that didn't change
anything either.

The load average on the LTSP server was around 1 with 6 clients
running tuxmath.  Memory was about 1Gb. So, my best guess is a network
bandwidth issue. Tonight I'll connect my newest server to that switch
and see if it performs better. Maybe it is just old hardware.

"Old" Gb switch uplinks should work as well as new ones if the cabling and configuration is OK.

--
  Les Mikesell
   lesmikesell gmail com


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