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Comparing and Contrasting Virtualized Servers and Microservers Page 4

Comparing and Contrasting Virtualized Servers and Microservers

You may already be comparing and contrasting the two options: virtualized servers and microservers. I prefer to contrast rather than compare them, but it's only natural that people will start comparing the options, so let's help things a bit.

The virtualized solution means that only one OS is actually installed on the hardware and then VMs are created as needed. But you have to create the VMs ahead of time, so it is somewhat like installing an OS, but it can be the same OS for each VM (meaning you only have to do it once).

In the case of the microserver, you have to actually install the OS on every server and manage it. If you are thinking that this means extra administration work because you are arguably dealing with 128 OS installations versus 2 for the virtualized server (1 system OS and 1 VM), you have a very valid point.

However, in the HPC world, administrators long ago came to grips with how to deploy a large number of servers with the same image and manage them so it's not an impossible task (HPC has been doing it for a long time). For example, TACC (Texas Advanced Computing Center) just deployed a cluster named Stampede with 6,400 nodes using a small handful of images for the entire system.

The virtualized server gives you the flexibility of moving a VM to a different server if circumstances change. However, if you need to do maintenance on the server forcing a reboot, then you will need a second system very similar to the first.

But virtualization gives you this flexibility. The microserver solution does not because there is no VM on the microserver — it's all bare metal. You could virtualize the microserver if you wished to handle these situations.

If, for some reason, the virtualized server fails, you then lose all 128 VMs. In the case of the microserver, if you lose a server, you only lose that single server, or 0.78% of the cluster.

The software eco-system around ARM processors is not the most complete. It seems as though each ARM implementation has a different boot mechanism and some variations in configuration. The virtualized server option has an advantage in this case because the VM is based on the same hardware as the server itself. The microserver world, specifically the ARM world, needs to catch up rather quickly relative to the virtualized world in this area.

Microservers: Up and Coming Solution or Cute Holiday Boutique Gift?

This is the title of this article and the originating question I used when starting the research. Microservers are becoming the rage because they are very small, allowing for very dense systems, very power-efficient systems, and presumably more cost-effective systems. But are they a truly viable approach for providing server resources?

In the comparison of microservers to virtualized servers I was truly surprised by the closeness of the results. The price and power of the two systems are very close to each other to the point where one can argue they are on equal footing (within 10%). However, the microserver is about 50% more dense, illustrating one of the draws of microservers: density.

There are aspects to both options that are appealing depending upon your situation. At this point, I think it is difficult to say with any certainty that one is better than the other although the software eco-system around ARM servers is still immature (but gaining speed).

Given the very strong roadmaps for both ARM processors and Intel Atom processors that have been discussed in the open literature, I think it's pretty safe to say that microservers are an up and coming solution. Are they valid today? Perhaps in some circumstances, but for the general case, perhaps not. But I believe they could be once the software issues are ironed out.

At the same time I think microservers could also be a cute boutique gift. My Raspberry Pi is utterly cool for many reasons. I'm working on my portable RPi HPC cluster now so I can freak out the TSA. That said, I will be giving myself an extra 2 hours to get through security in case they want to ask more detailed questions ... or in case they happen to be RPi enthusiasts as well.

This article was originally published on February 11, 2013
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