Saturday, September 06, 2008

Windows Server 2008 64bit crashing randomly after memory upgrade

I have VMWare Server 2.0 Beta x running on Windows Server 2008 Std 64bit. At only 2GB I can only run one virtual machine. So the machine was upgraded to 8GB! I didn't notice much performance improvement in the host machine but I can start kicking in four virtual machines. But.........

The big but.. was that Windows Server 2008 just crashes randomly. Sometimes just a few minutes.. booom it crashes. Digging a little further I was able to simulate the crash pretty easily. Remote the machine's console session (/admin switch in mstsc.exe) then login back to the host machine.

So I was thinking/asking myself, was it because of the new 8GB memory upgrade? It must be, but is it the hardware or software that does not like the upgrade.

Trying to eliminate variables, I booted the machine into System Rescue CD then run memtest for two hours. No dice here. So it must not be the new memory being faulty.

Digging more, I found out that there was a video error logged in Control Panel>"Problem Reports and Solutions".

So I was thinking then that this must have been a video controller problem or video driver issue. Back in XP days, as far as I know, the high memory area of RAM is being used to access to PC peripherals like PCI cards, shadow of video memory etc. So maybe, just maybe, the drivers where not designed for this large memory configuration. The drivers might have used 32bit addressing assuming that it will be only upto 4GB in memory but I got 8GB in the system. So all of the sudden the memory being allocated (assuming the drivers are using malloc) now returns incorrect values explaining the random crash.

Since the machine is going to be a virtual machine host, I don't need fancy graphics effects, in fact the machine can be headless. So I downgraded the video driver to MS Windows SVGA default driver. Low and behold it is now at last working without issues.

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