[CentOS] Ethernet poor performance
rgm at htt-consult.com
Wed Jul 2 16:40:15 UTC 2008
> Robert Moskowitz wrote:
>> Any Idea where I should look to fix this?
> - What version of CentOS?
> - What type of network card?
Intel the first time, DLink (Realtek) currently. Both 10/100Mb
> - What driver is it using?
How do I tell?
> - What type of device is on the other end of the network card?(Switch, hub,
> router etc)
The card is plugged into a switch. All boxes plugged into the switch get
similar PING results. Good with the internal (also Intel) card,
bad/very_bad with the PCI ethernet card.
> - Can you verify that the speed and duplex settings match on both ends of
> the connection?
The switch has its 100Mb LED on. One of the switch ports has my
Speedstream router which is only 10Mb, so we can believe the 100Mb LED.
This is a dumb switch (my public network, so I am not going to plug into
one of my Procurves).
> - I assume the ping you are running is only 1 or 2(if there's a hub/switch
> in between) hops away?
I have done it 1 hop (directly attached boxes), 2 hops, and somewhere
out there on the net (220.127.116.11, a great system to use as an emergency
> - Any errors reported by ifconfig ? any collisions?
No and no.
eth1 Link encap:Ethernet HWaddr 00:50:BA:42:82:49
inet addr:18.104.22.168 Bcast:22.214.171.124 Mask:255.255.255.248
inet6 addr: fe80::250:baff:fe42:8249/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1709 errors:0 dropped:0 overruns:0 frame:0
TX packets:1033 errors:0 dropped:0 overruns:0 carrier:0
RX bytes:535351 (522.8 KiB) TX bytes:117321 (114.5 KiB)
Interrupt:10 Base address:0xa000
ho, ho. MTU of 1500. Is this not doing MTU path discovery? But these are
little PINGs so there should not be any frag problems (my WAN link is
PPPoE, so you want pathMTU or have to hard config everything to
1415bytes per the pppoe man pages).
> - Try replacing the card itself? maybe it is bad.
On my 2nd card already.
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