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I have has some clients report that their download speed from my web and ftp servers max out at 4.5Mbps for them, to me thats awesome, but now i am wondering why it stop at 4.5. The services are separate service runnning on the server. When i test my speeds from speedtest.net it shows as

30 Mbps - Down

20.5 Mbps - Up

Apache is the web service running

VSFTP is the FTP service running, i checked the conf and the limit bandwidth is commented out.

The server has dual Gig NICs

OS: CentOS 6.2

CPU does not spike much at all and memory usage is very low.

Tomorrow i will test a download from another FTP server i have on another machine same network.

In var/log/messages i see eth0 showing up as

eth0: Link is up at 1000 Mbps, full duplex....

When i issue ethtool -a eth0 i get:

Pause parameters for eth0: Autonegotiate: on RX: off TX: off

When i issue ethtool -g eth0

i see current 256 and max pre-set 4096

I am not really sure what else i should post for information. I found someone with a similar issue, but they did not post what they tweaked to get a better speed.

I am happy to post whatever is needed to get my speed to go above 4.5Mbps. The client's connection is 8Mbps down and 1 Mbps up. They report at first the download whether FTP or HTTP spikes at 7Mbps then slows down and stabilizes at 4.5. Not sure where to start tweaking or if its not the server and it is my firewall or ISP. Any help is appreciated! Thanks in advance!

I was gonna follow this article : http://datatag.web.cern.ch/datatag/howto/tcp.html

Havent really posted much on here before so i apologize if i have left out any important details, just reply and i will add whatever is needed to get to a solution. Once solved i will add what i did to the OP.

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Did you checkout your IO subsystem? Use tuned-adm (yum install tuned) to tweak your kernel - 'tuned-adm profile throughput-performance' –  tigran Nov 12 '13 at 6:34
    
will do in a few min, in the other post someone mentioned to try: "you need to distribute the load across all CPU cores. Start 'irqbalance'" what so you think about using irqbalance as well? –  WifiGhost Nov 13 '13 at 2:11
    
apparently already had tunes installed, ran tuned-adm profile throughput-performance, ill see how it goes, also started irqbalance –  WifiGhost Nov 14 '13 at 5:43

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