Performance problem

[EGR]

Hi,

we have got some trouble in our network.

- about 30 workstations, W2k Pro, SP4; Win XP Pro, SP1 (Realtek 100Mbit /Broadcom 1000Mbit)
- 3 Windows Server (2x W2k3, 1x W2k Server, HP ProLiant DL380/ML 350))
- 3 HP switches gbit, 24 port
(2 of them cascaded with CAT5, one over Fiber Channel (distance 50m))
- in some (3-4) rooms there is a small Longshine 8-Port 100Mbit Switch
- default gateway is a Watchguard Firebox 2500
- and then there is a small Cisco DSL Router (don't know which one, but it is about haf a year old)

The problem is, that we have got a very poor performance.
Everything works (ping, domain logons, Backup etc.) but slow.
So it takes about 2 hours to copy about 700MB.


I'm not very into network troubleshooting, so do you have a plan how to proceed?
Would be very nice if you could give me some hints how to chronological go on and what to check so that the problem can be solved fast.
Links to webpages with troubleshooting guides are welcome, too.

Thanks
/egr

 

[Parcival21]

Maybe just start with some tracert commands to check which way the packets go to their destination adress.

 

[jimbopalmer]

I have a FAQ here in the ethernet forum on why mis-configured duplex can slow performance, it may help. I would be very concerned about the Fibre Channel link, I have not used fibre channel, and am not sure why you are, but I have used all forms of Ethernet over fiber, and you HAVE to make sure both ends are set the same.

"All computers set to auto, all switches set to auto except one fiber link set to full at each end." would be my reccommended starting point.

Are the HP switches managed? can you read the port statistics?

I tried to remain child-like, all I acheived was childish.

 

[kmfna]

if your workstations have gigabit capabilities, you could upgrade your switch to a gigabit switch....so that you aren't bottlenecked...you could also consider upgrading all of your boxes to have Gb cards and have a true Gb Network...at least it would make internal dealings fairly fast.

Good luck
Kevin

- "The truth hurts, maybe not as much as jumping on a bicycle with no seat, but it hurts.

 

[bcastner]

See the registry changes suggested by Microsoft:

http://support.microsoft.com/?kbid=315237

 

[mpennac]

Here is how you troubleshoot a network slowdown such as this:

1) Go out to

http://dast.nlanr.net/Projects/Iperf/#download

2) Download IPERF, it is a 100KB executable.

3) Put a copy of IPERF on the server. From the DOS prompt run iperf -s. This will put the server in listening mode.

4) Put a copy of IPERF on a workstation that is experiencing poor response times.

5) At the workstation's DOS prompt type iperf -c [server ip address]. IPERF on the workstation will connect to the IPERF on the server on TCP port 5001. For 10 seconds it will transfer as much data as it can. At the end of 10 seconds, it will report the throughput of the network. If this value is less than 80 megabits per second, you have problems.

6) If the throughput is good, reverse the test. Run iperf -s on the workstation and iperf -c [workstation ip address] on the server. If this throughput is bad, you have a duplex mismatch. When testing with IPERF, you will find that if a duplex mismatch is present, you will get good throughput one direction and poor throughput in the other.

7) If you get good throughput in both directions, your problem is not the network infrastructure.

It is my belief that in a case like this that upgrading to Gig only complicates the problem resolution. You should be able to move 10 megabytes per second across a health 100 mbps network. This being the case you should be able to move your 700MB in just over a minute.

Here is one other thing to check. During the file transfer run netstat -s on both the client and the server. Under the TCP section, check out the Segments Retransmitted. If this value is incrementing, you are losing frames between the client and the server. This can be another indication of a duplex problem, or bad cabling.

Make sure everything is set to auto negotiation. Sounds crazy, but if one end is set to auto and the other is force to 100/Full, you will have problems. If everything is forced to 100/Full, it should work OK. I have seen where some servers will revert back to auto after a reboot though.

Happy troubleshooting!

mpennac

http://www.netprospecialists.com