1st of all, the reason of being utilize blade system in the market are looking at the point of servers consolidation, reduce power consumption and reduce the TCO require to purchase in term of hardware compare to the 1U, 2 U and 4 U servers. When we do compare the reason of having blade, you will always notice it was comparable between 2U and 1U servers in the x86 family and data center environment. In large scale deployment, you will always see that the Blade allow you to scale and spend in the sense with more stand alone machine you can have with the limitted rack space and power you do have in your DC. These seems to make sense for us to start moving to blade, BUT it also have some risk which will become major issue later on.

Before you can use blade, you require higher power consumption per rack to support approximately 30 to 32 blades per racks on 42 servers rack. At the same time, the cooling unit design in you DC require to be customize to ensure your blade chassis is working in perfect condition. Once you have this, then you may able to start think about Blade.

ESX on Blade have been some idea I personally thought before. The products I specify looking is the latest DELL Blade M1000e. The power and cooling in my DC is not a big issue. When I do analyzed the possibilities, I found couple of show stopper to deny my decision to move forward on that. As the enterprise architect point of view, Blade will be more suitable to consolidate those machine which require to run on physical VS Virtualization. The reason of that, is not really the matter of CPU or Memory you can have in the single blade, is really about the redundancy and performance we focusing on our virtualization. The limited number of pass through, NIC, and FC per blade is really not able to meet the number of VM we tried to achieve per host. We require redundancy, teaming as well as performance through put in term of networking and storage with the ESX servers we have. When we do calculate in term of cost per VM, the number had not show up as significant saving as we expected.

In additional to that, the more ESX machine we have in our Virtualization farm, it always require additional efforts to manage it for long term basis. There are many cases that users had built the ESX server with only 2 gigabits NIC for VMnetwork, which end up facing the performance issue in term on the Networking as well as the single point of failure. Virtualization is not performance sacrification. If we do plan properly, we will gain performance in virtualization vs under utilization physical machine.

Here is those finding I have and I will say that the Blade will not fit the virtualization requirement to achieve High availability and performance requirement. If we will have enough money to be spent on Blade environment, I believe you should have sufficient budget to go for something more suitable like R900, R905 and others 4U servers which provide more memory and CPU you need.