Moving from windows to Kubuntu on a business work computer – Part I

I’m moving my work laptop to Kubuntu leaving Windows behind. Despite my company having Microsoft licensing for all computers and for a lot of products, I’m jumping out of the bandwagon…

The computer is an HP nx9420 with and 100G SATA hard disk, and so far so good, everything looks to work fine, including Wireless, Bluetooth, except the integrated smartcard reader. But this can be a problem on the OpenCT software, not on Kubuntu Hard Heron 8.04 release. Using the Gemplus USB reader works perfectly.

Evolution for connecting to exchange does work, but it has some stability issues and some quirks that I find annoying… but otherwise it can replace Outlook without any problem, and have at the same time email accounts open like Gmail, and other IMAP mail accounts. An annoying thing is it can’t remember already used e-mail addresses, or looking at the Personal directory if your using the Global catalog server for finding emails so you have to type them if they are not on your GC. I must look for a solution to this.

VMWare server and VMware converter allows to run some software that I really need and has no counter part on Linux World, like Visio and the proprietary software that my company works with.

Also 2X Application server allows you to run Windows applications directly on your Linux Desktop, so you don’t even need to use the VMWare console to work!. And it’s free for 5 connections after the 30 day trial period.

I’ll get back later on this

Windows 2003 slow network application performance

I was bitten very hard for something that is quite hidden and took a while to figure it out.

Moved an application from Windows 2002 to Windows 2003, and in the moving process, services that where on the same machine moved to different machines, which in turn means that they would use the LAN to communicate between them instead of the loopback adapter.

Well just imagine an application running on top of the line servers (8 CPU’s, 10GB RAM) running slower than a six year old server…

The main clue that something was blocking the performance was that there was no CPU load. So the application was not processing anything, just waiting…

Or friendly tool started to bring some light on the issue. It seems that most of the times between packets namely the between the PSH/ACK and the answer took around 200ms. Again processing the application log files show a lot of processing time under 10ms and a “bump” around the 200ms mark.

To make a long story short… Despite of most of Windows server deployments being made on high speed networks on enterprise LAN segments, Windows 2003 has by default an TCP/IP algorithm called nagle active so it can save bandwidth on slow WAN links!!!!!

What does it mean? It means that Windows will reply right away with an ACK packet if it has data to transmit back, so it piggybacks the ACK with the data saving packets. If it has no data it times-out after 200ms and then sends the lone ACK packet… Meanwhile the 1/4s as passed by. Small number theory says that a lot of small numbers added up give on big number, hence seconds of pure slowness.

For all your LAN throughput can be used by your applications you need to switch off the 200ms delay:

Here’s how:

After the above documented change, well the application just caught fire and ran like a rocket.

Update: Also check:

Update2: Also check: -> This will disable some “features”…