Virtualization

[bigbearomaha]

I have a question for anyone who cares to add to this discussion.

We see articles all the time on Virtualization and the perceived benefits of using it, especially in Linux discussions.

While many people extol the virtues of conserving and making the most of hardware resources and financial savings due to needing less hardware, there is another line of thinking that falls under the
"Don't put all your eggs in one basket" theory.

While using virtualization can sometimes maximize efficiency or get the most out of a machines resources, it all places the dependency on less hardware . Kind of like the old Stereo systems.

Before there were component systems, each function had it own box, tape deck, cd player, radio, turntable, mixer, amp, etc...

Then, they introduced integrated systems which put all those things in one box.

Nice to save on space, weight, etc.. but, if one of those functions goes out, you are out of the whole shebang while it is being repaired. Or you need to buy another whole new system rather than just repairing/replacing the one malfunctioning item.

Seems to me and others I work with, the same goes for servers with virtualization. It's neat to maximize resources by running x number of virtual machines doing various things on one actual machine, but if that computer takes a dive, there's more work and downtime in getting x number of servers machines back up instead of just the one or so you may have been running on one machine.

Especially in mission critical situations where downtime is a virtual nono.

So, I and other techs who I know that think similarly, that virtualization in the server world is overhyped, are always being told we're 'missing the boat'.

In my opinion, have a better chance of staying afloat with a lot of smaller boats than dying with everyone on one big boat.

Any thoughts?


(btw This is not to say that virtualization doesn't have it's strong points, just moreso in the development arenas, perhaps isolated incidents elsewhere)

Big Bear

[Carla Schroder]

In my opinion, have a better chance of staying afloat with a lot of smaller boats than dying with everyone on one big boat.

It all depends on the quality of your boats. If your big boat is a well-designed, well-built machine that uses real server hardware, and has multiple hot-swappable disks, power supplies, and other hot-swap components, and good backup power, then you're not going to see much downtime. Machines of that class are known for running continuously for years.

PHBs love cheapo PC hardware because it is cheapo. If you can tolerate occasional downtimes, better-quality PC hardware saves money and performs just fine. You can have a whole second duplicate machine for failover and still have money left over.

Don't forget power consumption and space. More machines = higher power consumption, and more demands on your cooling system.

Another consideration is your operating system. A lot of these virtualization schemes are based on the assumption that all servers need to be dedicated and not shared- Web server only, mail server only, and so forth, because if one is compromised then all are at risk. Maybe in feeble, malware-friendly Windows-land this is a primary consideration, but Unix/Linux machines can run all kinds of servers efficiently, and if you use AppArmor or SELinux for security you can make them nearly bullet-proof.

As always, the definitive answer is "it depends." :)

[bigbearomaha]

There are a lot of 'what if's" there.

many small business or server users will not have access to "real servers' in terms of hardware, and Linux is constantly touted as being able to run "big" servers on the 'small' machines.

In the corporate world, having access to that kind of equipment is much more prevalent.

and the scenario of having backup equipment, etc... is exactly what one would recommend for recovery purposes or should be. Must agree on that.

Unfortunately, For every 'solid' built boat out there, there are a lot of "Titanics' those touted as unsinkable, only to fall apart as soon as the warranty is up. We have all seen those machines.

Like you said, it does depend on environment and scenario as well as how much $ one is prepared to spend in terms of hardware and recovery/backup.

I guess I was writing from a frustrated POV of reading yet another article of how virtualization is the end all be all solution of the future.

And that is a boat I cannot get on.


Big Bear

[Carla Schroder]

Virtualization is definitely over-hyped. Like so many things :).

[wmstudio]

I think virtualization has many advantages and over-hyped? Yes perhaps by all those who talk about it and have no idea what they are talking about.

Apart from the fact that you can save on hardware and energy it's also a nice thing to have your OS/Application more or less independent of the hardware layer.

For instance if you have slow hardware or hardware that needs to be replaced then it's simply a matter of moving/copying your virtual machine image to (another) machine(s) and presto you're up and running.

For some VM's (VMWare) you don't even need to shutdown your VM in order to move the VM. You configure your VM layout on-the-fly. Try doing that with a non-virtual machine environment.

You can also make dedicated VM's (appliances), dedicated to one task i.e. For example you can create a VM mail server. If for some reason you need additional mail servers, then copy the VM mail server to the same of additional hardware systems.

You can even design appliances and give/sell them to others....