Scott Dowdle's blog

KVM = Kernel-based Virtual Machine

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It seems that a sort of hypervisor is going to be added to the mainline Linux kernel. It has been dubbed KVM... as if KVM weren't already taken by "Keyboard, Video Mouse". In this case, KVM stands for Kernel-based Virtual Machine... and it only works in CPUs that have VT (Intel) or AMD-V/SVM (AMD) extensions via a module named kvm.ko... and will available upon the release of the 2.6.20 kernel.

How does it differ from other virtualization schemes? From the FAQ:

What is the difference between kvm and Xen?

Xen is an external hypervisor; it assumes control of the machine and divides resources among guests. On the other hand, kvm is part of Linux and uses the regular Linux scheduler and memory management. This means that kvm is much smaller and simpler to use.

On the other hand, Xen supports both full virtualization and a technique called paravirtualization, which allows better performance for modified guests. kvm does not at present support paravirtualization.

What is the difference between kvm and VMWare?

VMware is a proprietary product. kvm is Free Software released under the GPL.

What is the difference between kvm and QEMU?

Qemu uses emulation; kvm uses processor extensions for virtualization.

And now for the question everyone wants to ask:

What OSs can I run inside kvm VM?

We have tested Linux (32/64 bit) and Windows (32 bit). Others may or may not work. 64-bit Windows is known not to work. This will be fixed once qemu-0.8.3 is released and merged. Several Linux flavors are known to hang on Intel processors during startup. Workaround is to disable splashscreens in grub.

I wonder how long before this becomes part of all of the distributions... and how it might conflict with Xen???


What to do with an old server?

Front viewFront viewI have an old server at work. It hasn't been used since last Spring. It lasted a fair amount of time (4 years)... yet it is still a fairly capable machine: 1.1GHz Xeon CPU, 2GB of RAM, 1 IDE system disk, a 3ware ATA RAID controller with 8ea 80GB drives (RAID5) and redundant power. I believe it was purchased in late 2001.

One of the RAID drives died and I put in a replacement today. I didn't need to rebuild the existing RAID because I wanted to do a new install anyway... but it makes me wonder if I should even bother. Side viewSide viewI mean, the drives that are in it now are at least 4 years old. They are an accident waiting to happen. So, I have a few options... I can retire the machine and scrap it... or I could spend around $800 and buy some new ATA drives. I figure that the hard drives are the most vulnerable piece in the system... other than say... the fans... that I'll replace if they are showing some wear.

Back viewBack viewIs it worth the money to turn this machine into a backup server? ...or should I just retire it? Do you think the hardware will last a few more years? It would run Linux of course. It was previously.

Let comments be your answer!


Getting those Apache/PHP settings just right

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Warren is the guy who has been running Gallery for a few years now. Me? I ran it at my previous job but I didn't get into it much.

Cybernet PCCybernet PCNow I'm running Drupal and on the default Apache/PHP install, PHP is limited to 8MB of RAM. That works fine for most everything... but when you get into graphics processing, it isn't even close. Graphics Processing? The image upload (and photo gallery) module for Drupal take an uploaded image file and then generates a preview size (640x480) image and a thumbnail (125x125?) image. It can use ImageMagick or the GD image processing packages.


Beyond Belief 2006 Videos

Over the 2006 Thanksgiving holiday I stumbled upon a series of video presentations that were given at the Beyond Belief 2006 conference. "What's that?", you might ask? From the description on the website:

Just 40 years after a famous TIME magazine cover asked "Is God Dead?" the answer appears to be a resounding "No!" According to a survey by the Pew Forum on Religion & Public Life in a recent issue of Foreign Policy magazine, "God is Winning". Religions are increasingly a geopolitical force to be reckoned with. Fundamentalist movements - some violent in the extreme - are growing. Science and religion are at odds in the classrooms and courtrooms. And a return to religious values is widely touted as an antidote to the alleged decline in public morality. After two centuries, could this be twilight for the Enlightenment project and the beginning of a new age of unreason? Will faith and dogma trump rational inquiry, or will it be possible to reconcile religious and scientific worldviews? Can evolutionary biology, anthropology and neuroscience help us to better understand how we construct beliefs, and experience empathy, fear and awe? Can science help us create a new rational narrative as poetic and powerful as those that have traditionally sustained societies? Can we treat religion as a natural phenomenon? Can we be good without God? And if not God, then what?

My first blog entry

Ok, with blog entries... I *BELIEVE* I can have a personal blog that isn't tied to the main content of the site. In fact, all registered users will be able to have their own blog... which is quite useful.


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