Virtual Insanity...

[jsbowden]

Okay, so I've been playing with virtualization over the last few weeks (VMware, Virtual PC, and XEN), and I'm kind of not seeing the point.

Okay, loading up Virtual PC on my machine at home, and installing Win98 so I can play old games is nifty and all (and hey, my motherboard even has hardware support for VMs, which Vitual PC can and does take advantage of...), but the whole server virtualization thing eludes me.

I mean, how is running a bunch of VMs is any less resource intensive than running a bunch of jailed processes (or, chrooted if you're still living in the dark ages :P)? In fact, as far as I can tell, it's MORE resource intensive, since I have to dedicate hard amounts of memory to each VM, where jails just use memory as needed out of the system total. I'm going to be running the same services either way, I don't see less processor cycles used, it's more, actually since that VM's local OS has its own overhead it has to take care of.

Am I missing something here? This looks like a solution looking for a problem. I can see where it could be useful in the same way building a bootable CD/DVD to run an OS off of is useful, except less secure since the VMs disk image can be fucked with, unlike immutable optical media.

EDIT:

So, after chatting with some friends, it seems VMs make things like patching and DR easier, which I can see, and it abstracts HA out to an easier to manage level, which is nice. Still, not going to save the planet moving everything to VMs, and some things still belong on dedicated hardware (which, may mean a single host/guest arrangement if you're hardcore on doing VM everywhere, no matter what).

Comments

[sungo.livejournal.com]

I think what you're missing is that most of the VM crazies are linux folks. Last I knew, our "jail" options are the aforementioned annoying chroot or something like xen. Jail will always reign supreme but us linux folks are kind of left out of that glory.

The other big win is for hosted setups. Team A needs to run shit on your hardware but they want to manage the OS. Well, now they can and they won't have as big an impact on anything or anyone else on the system.

I also have this same thought pattern about blade servers. Everyone things they'll save the world and the tech economy but they're really only great for a few applications.

[corruptedjasper.livejournal.com]

Blade servers are actually likely to destroy the world. On a per-CPU basis, they're neither that cheap nor that low-power, and on a per-rackspace basis they draw like three times the power of 1U machines (which are like three times more power than the 4U machines many datacenters were built for).

Unless you have very specific needs and your power supply and AC are designed for them, blade servers save a little space and very little power, which means that you'll have to keep empty spaces open to compensate. Might as well just rack regular machines, just like google does.