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Citrix XenServer Virtualization Platform Now Free
Pedro writes "Citrix announced today that they are giving away their Xen OSS based virtualization platform XenServer with all the goodies included for free. The big highlights are XenMotion, which lets you move VMs from box to box without downtime, and multi server management. The same stuff in VMware land is $5k. They plan to sell new products for XenServer and also the same stuff on Microsoft's virtualization technology called Hyper-V. It will be interesting to see what VMware does. The announcement comes the day before VMware's big user event VMworld."
VT changed the game. Nowadays Xen (and others like Sun's VirtualBox) runs Windows just fine.
It's sad to notice that both VMWare and Citrix are neglecting building non-Windows management clients by the way :(
You're describing the practice of using virtualization to host multiple dedicated-purpose "appliances." I use this approach myself; I've got a Debian VPS doing proxy work, another couple of nodes for static HTML serving, another for dynamic apps, one that just serves as an XHTML validation server, etc.
Hardware is cheap these days, and virtualization makes the clean separation of appliances on a single managed box very easy to accomplish.
At one installation I managed, it was decide that the single (Linux) "server-that-did-everything" approach would be scrapped in favor of multiple virtualized appliances.
Without boring everyone with the details, the "experts" brought in to do this left with tail between legs when it was found that the harware previously used, and which never exceeded 2% CPU Utilization, was woefully inadequate to handle the four virtual machines into which it was virtualized.
New hardware was going to be needed. The manager sent the experts packing, and paid his in-house staff overtime to restore the system to its prior state.
Virtualizing an entire operating system to run a single system for the sake of simplicity is still absurdly wasteful of CPU cycles, memory, and disk space.
NO, New hardware is not cheap.
Anyone who believes it is cheap is looking only at the sticker price and not the staff, power, cooling, backup, rack-space, setup-time needed.
To use the cheapness of new hardware as a justification for virtualization is to turn the whole Virtual Machine concept on its head.
At the end of the day you have to ask: Why vitrualize if doing so means you are going to have to buy new hardware? Just buy the new iron and split out your functions across different platforms and take advantage of the redundancy, and reliability of not having all services disappear do to a single component failure.
Sig Battery depleted. Reverting to safe mode.
I can't speak to what happened in your particular scenario, but yes, staff, power cooling, etc. are big drivers for virtualization. I've seen multiple racks of servers condensed down into two servers and a SAN running in about 20U. You can get to everything remotely (out-of-band) without needing an IP-KVM and can restart hung servers without needing an IP/Serial PDU.
Setup time for new servers is orders of magnitude faster. fill out a couple screens in a click-and-drool GUI and you have a new server up and running.
Redundancy and reliability are also quite a bit better. While you're right a catastrophic failure of physical server hardware will bring down the VMs hosted on that server, they can immediately be powered on again on one of the other physical hosts. (Of course if you use local storage with virtual servers, you're playing with fire and will get burned eventually) Virtualization also makes it reasonable to cluster services for HA since you don't need 100% more hardware for failover. VMotion or XenMotion (which I haven't yet tried) will let you move running VMs off a physical box you suspect of failing or need to service which is damn handy, though I don't know that it's worth the price VMWare charges in most cases.
Virtualization means NOT needing to buy new hardware since the hardware becomes a commodity, run it till it fails and then replace it. You get out of proactive replacement cycles and expensive 7x24x4 support contracts. When you need more capacity, you just add another node and redistribute your VMs rather than having to deal with the headache of migrating an overutilized server to new hardware.
Fsck the millennium, we want it now.
Millennium Crisis Line: 0890 900 2000 [calls cost 50p/min]
Running everything on a single OS image, when correctly configured, gives a pretty significant performance benefit.
And pretty significant maintenance COST. Running everything on a single OS image means you have to:
a) settle on one OS. you cite windows VMs being common because apps often don't play well together. In my experience, Linux really isn't much better... lots of apps are only vender supported or fully compatible with a limited set of distros or distro versions with specific package version requirements, deviate outside that and your on your own...
With VMs you can trivially run product A in RHEL4 and service B in Debian, and simply not have to worry about it.
b) any time you make a change to any of the services on the image, you have to retest and validate the entire image to ensure nothing broke. If I'm running A and B, and an update to A requires me to update perl or python... and B also uses perl or python than you need to potentially extensively re-test B to make sure it still works.
c) when one of the services load grows its trivial to migrate that service to a new physical server without doing a ton of work building a new image, moving data, testing it, spinning the service down on the old server, etc. Granted, running VMs means overhead that will mean you will have to migrate the service earlier than you would otherwise... but the savings in effort when actually moving it more than makes up for it.
In my experience. of course. YMMV.