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Virtualization Frontier

3 Posts tagged with the recommendation tag
1

After spending the last few weeks looking into which server to choose for virtualization, a natural next question is - What should I use for storage? I think that the answer here may be easier in some ways, but more complicated in other ways.

Mark Farley, on the InsideIT blog, highlighted a recent video by Darren Thomas, General Manager of Storage - aka Chief Storage Guy - here at Dell, that focuses on how storage virtualization works well with server virtualization. Just as VMs are able to use live migration to move from one physical server to another, virtualized storage can move those same VMs from one storage array to another. The result is that you have a tremendous amount of flexibility and availability.

There are three major categories for storage: local, iSCSI, and Fibre Channel. There are lots of choices within these, but I think that when deciding what to use to support your virtualization servers this is the best starting organization. If you are going to only have one virtualization server (or one per location) then local storage will work just great. If you already have an existing fibre channel SAN and existing expertise to manage it, then fibre may be the best solution for your virtualization server farm. Everybody else should probably take a really hard look at iSCSI.

Within the iSCSI category at Dell we have three areas to pick from: PowerVault MD3000i, Dell EqualLogic PS Series, and Dell | EMC AX and CX iSCSI arrays. I think that the decision here also breaks down very similar to how we arrived at the type of storage. For smaller deployments or those that do not need array level features like replication the PowerVault MD3000i (with an attractive entry-level price) is a good choice. For customers that already have some Dell|EMC fibre channel or iSCSI it might be a good idea to extend this environment with additional iSCSI for your virtualization needs. I think that the Dell|EqualLogic PS series is a strong contender for all other solutions.

Of course it's really a bit more complicated than this, but this is the way that I frame up a conversation around storage for virtualization solutions.

Todd

1 Comments Permalink Tags: recommendation, storage, iscsi, fiber, md3000i, equallogic, delltechcenter
0

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

0 Comments Permalink Tags: delltechcenter, techcenter, 4-socket, 2-socket, blades, chat, r805, hardware, recommendation
0

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

0 Comments Permalink Tags: 2-socket, 4-socket, blades, vmotion, hardware, recommendation

ToddMuirhead

 Member since: Feb 13, 2006

Some Stuff on Enterprise Virtualization from DellTechCenter

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