Blog Posts

What is the best server for virtualization? This is a question that comes up often in discussions, although it is sometimes phrased differently. It might be "How many NICs do you recommend for ESX?" or "How much RAM can you put in an R805?" or "Are blades the most power efficient server?". The really cool thing is that the answer to all of them ends up being the same - If you can tell me what you are trying to do, and the key requirements that you have, I can give you the best answer. Sometimes you need tons of RAM, sometimes you oodles of NICs, and sometimes you are looking for the best value.

We can give you some basic guidance and even provide you with reference architectures, but ultimately everybody has to customize their virtualization solution based on their needs. To provide you with the ability to be able to customize, you have to be educated about what your choices are what the ramifications are for each choice. That's what this focus topic on Selecting a Virtualiation Server has been all about. Connecting people with the information as well as each other for discussion about the process. This played out in each of the three chats that we did, and can continue on the discussion threads.

This really isn't anything new in the IT world. Almost all solutions have required a certain amount of planning and sizing that was specific for each organization. The advantage with virtualization is that there is more wiggle room to adapt and learn as you go. Because virtualization provides a layer between the VMs and the physical servers, things can be changed, modified, tuned much more easily than without virtualizaiton. If you find that a server is overloaded with too many VMs, you can use VMotion to move some to another server. If you find that you are out of capacity, you can add another server to the farm and redistribute the VMs to take advantage of the new capacity - without any downtime.

Use this community to keep the discussion going about what the best server is for virtualization - all questions around this topic are welcome. The opportunity to interact with your peers and find out why and how they made their decisions is really the best answer to a question that has a different answer for everybody.

Todd

On the TechTuesday chat yesterday the topic was Selecting a Server for Virtualization, and we had an excellent discussion. One of the points that came up was the importance of understanding VMotion compatibility between different servers. On easy rule is that it is not possible to VMotion between AMD and Intel processors. As these are completely different processors in many respects it is easy to understand how it is not possible to move a running VM from one to the other with no downtime. The next aspect that VMotion will not work across different generations of processors. The difficulty here is that processor generations do not always line up with Dell server generations. So even if you have all Dell 9G servers, there are cases where VMotion will not work.

It really comes down to the instruction set that each processors is using. A running VM has identified the processor that it is running on and is expecting a certain instruction set to be available. If this were to suddenly change in the middle the OS would not be able to cope or adapt and would most likely crash. There has been some work done to improve the situation - but as of today it is still an issue.

The answer to this problem is the compatibility matrix that our virtualization engineering team has put together and updates as new servers are released. It is important to consider this matrix when selecting a server if VMotion is in use.

Todd

For the past three weeks, we at the Dell TechCenter have been focused on the decoder ring for systems management. Starting today we are going to tell you what the best server is for virtualization. The reason it is going to take three weeks is that the answer for everybody is different. So we are going to talk about key factors, advantages of one type of server over another, and learn from the decisions and thought processes of each other. We are simply hosting the conversation and I do not have a "favorite server" -- although I must admit that I used to lean heavily towards 2-socket servers.

The decision for most seems to come down to 2-socket, 4-socket, or blades servers. I hope that we end up expanding the conversation and talk about lots of other possibilities including storage options, hypervisor options, and who knows what else.

In order to get things going are going to have some chat sessions, there is a topic home page, and a server selection matrix page to specifically lay out the facts about each type of server. I've started the page off with 2-socket, 4-socket, and blades as server categories with some basic tech specs and advantages for each type. This page will grow as additional pros, cons, and others ideas come up.

Todd

With the release of the 2U, 2-socket R805 and the 4U, 4-socket R905 (both AMD based servers) and the already existing 4U, 4-socket R900 (Intel based server) now is a really good time to be looking for a server to run your virtualization farm on. All three are excellent choices and could be the right server. To determine which one depends on lots of things. I'm looking for reasons to choose one over the other (let me know your thoughts). We will be putting together some information to help people decide here on TechCenter and hosting some chat sessions to enable discussion.

Specifically, I ran across this article from The Register that I think has a pretty good take on the R805/R905 Virtualization announcement from a couple of days ago. They point out all of the server options as well as the virtualizaiton services that were a part of the announcement on Tues.

Todd