Slow network performance with W2K and NOT XP

[doubleH]

Howdy,

I am starting to do a parallel migration from our legacy network to our new HP network consisting of 2 5406's and 1 3500.

I know this sounds weird, but I am having performance issues with only Windows 2000 SP4 pc's and servers and NOT with Windows XP or Windows Server 2003. When I say performance issues I mean latency. On a 2000 workstation I can ping its local gateway and get <10ms response time. If I do the same thing on WinXp I get <1ms which is what I expect. I've proven this by taking a WinXP machine and plugged it into the same network connection that the W2K pc was using and don't have latency. I even rebuilt the W2K pc with XP and am now getting <1ms response time. On the W2K pc I made sure that the nic drivers were up to date and also tried hard coding the speed/duplex settings on the pc and switch with no luck.

Thanks

[Bruce Campbell_3]

This is just a wild guess, but any chance
the time resolution on the older OS's are
10msec, while the new OS is 1msec ?

Do you see actual performance problems
copying data ? Like if you have a
genuine 10 millisecond per packet delay,
your throughput will be pretty awful,
max 150kilobytes/sec or so.

[Matt Hobbs]

Bruce is spot on. It's just the ping application under 2000 won't go any lower than <10ms.

If you run a packet capture you will see the actual response is much quicker.

[doubleH]

I wish it was cosmetic like you are indicating, but in this case it is not. Performance is very slow especially when running on of our main applications. I should note that the application ran fine on my legacy network.

Thanks

[Matt Hobbs · Accepted solution]

If it is Windows 2000 only, then you may benefit from some TCP tuning parameters. This page has some good information and link to a PDF Microsoft Document.

http://rdweb.cns.vt.edu/public/notes/win2k-tcpip.htm

The fact that it was running fine on the old network is hard to explain, but I think you should focus on the OS rather than the new network infrastructure.

This application that is suffering, can you share more detail about it?

What about basic file copy tests?
Windows 2000 Server > 2000 client = ?
Windows 2000 Server > XP client = ?
And the same tests for 2003 Server.

For much better throughput testing I would recommend using iperf: http://dast.nlanr.net/Projects/Iperf/

With Windows 2000 you will never see it display less than <10ms, to truly see the ping response you will need to use a packet capture application like Ethereal.

[doubleH]

awesome thanks. i adjusted the tcpwindowsize and performance appears to be back to normal!

[doubleH]

Looks like I spoke too soon. Things just seem a little pokey on the new network. My backups are now suffering and they are taking an extra 2 hrs longer to complete then when on the legacy network. The legacy network is a 100FX network. I migrated the backup server (W2K SP4) from its 100FX network to 100/1000T and the performance deteriated. About 50% of the servers, and few test pc's and a couple of printers are on the new network.

There are also some XP pc's that again seem pokey when I used their 1000T nic compared to when they were on the 100FX network.

I looked at iperf, but couldn't figure out how to run under windows. Can anyone recommend a windows based tool that will tell me what is going on the new network?

[Sergej Gurenko]

Try to enable qos pass through mode on a switch. ( http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=1002810 )
Try to connect all gig NICs to one switch, and all the 100mbps NICs to another (if there is a possibility.

[doubleH]

the 'qos-passthrough-mode' doesn't appear to be available on my 5406's.

[Matt Hobbs]

With iperf you simply set one side as the server and one as the client:

server: iperf -s
client: iperf -c

You can set a lot more options if required, the default test is 10 seconds so I increase that to 60 seconds with this:

iperf -c -t 60 -i 10

Looking back at your network, if you do a 'show span', how long ago was your last topology change? If it is in the seconds or even the minutes that is probably going to be your problem. Otherwise look through the port counters to try and see anything unusual there.

Otherwise if you can post a copy of the show tech from the ProCurve switches, it may help (remove any sensitive info, public IP's or SNMP community names).

Make sure you're running K.11.33 on these switches too.