Extreme Slowdown using Gb Network
dhubbard at dino.hostasaurus.com
Tue Mar 25 12:49:00 CST 2003
Try running this script and see if it helps:
for f in /proc/sys/net/ipv4/conf/*/arp_filter; do
echo 1 > $f
for f in /proc/sys/net/ipv4/conf/*/rp_filter; do
echo 1 > $f
From: Seumas Macmhicean [mailto:seumas at realise.com]
Sent: Tuesday, March 25, 2003 11:19 AM
To: linux-poweredge at dell.com
Cc: Unix Support
Subject: RE: Extreme Slowdown using Gb Network
I'll reply to a couple of responses at once - thanks all for
>You said that "all other boxes on the network experience a
>slowdown" when copying large files. Do you mean that Box C is
>delivering data to the public network when Box A is copying
files to Box
>B on the private Gb network? Or is Box C slow in talking to
Box D on
>the private network when the transfers are happening?
To clarify - when copying largish files between boxes A and B,
all other boxes become
very unresponsive in general usage - reports on CPU, disk,
network and so on all appear normal.
Nothing appears in dmesg nor messages, but the other boxes chug
- even doing a simple 'ls'.
>What do the network traffic lights look like on both switches?
It's in the Co Location facility... will have to check another
>Is there anything strange in the output of sar -n eth? on
>transfering and non-transfering systems?
We're going to investigate this.
>You could be having problems with the nics advertised
auto-negotiating and having problems with renegotiating
>during a heavy network load.
We're looking at ethtool but it seems to break the interface -
we'll keep at it and see if we can switch off the autonegotiation since
we don't need it (all devices on the network are the same - tg3)
>This may sound like an obvious step, but have you verified that
you are using cat5E and not cat5 on these?
Interesting point - the cables were bought new for this build
and are about 2 months old - will have to check them explicitly (again -
Co-Location facility) but aren't they all Cat5e compatible nowadays?
Still, something to check.
>Which model switch?
NetGear GS516T - bog standard config-free Gb switch
>Possibly, but any modern network switch acts as a multi-port
>your other boxes should not even see traffic.
Of course... but the effect is there - we'll do some more
thorough checks to make sure though... Hmmm. Faulty switch?
Something very odd is afoot here...
This electronic message contains information which may be
privileged and confidential. The information is intended to be for the
use of the individual(s) or entity named above. If you are not the
intended recipient, be aware that any disclosure, copying, distribution
or use of the contents of this information is prohibited. If you have
received this electronic message in error, please notify us by telephone
on 0131 476 6000 and delete the material from your computer.
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the Linux-PowerEdge