Choosing a Server Platform
Right Server for the Job!
Selecting the appropriate server is undoubtedly the first step in ensuring a successful vSphere deployment.
In addition, it is the only way to ensure VMware will provide the necessary support. Remember though a bigger server isn't necessarily a better server!
The second major decision to make when planning to deploy VMware vSphere 4 is choosing a hardware platform. Compared to "traditional" operating systems like Windows or Linux, ESX and ESXi have more stringent hardware restrictions. ESX and ESXi won't necessarily support every storage controller or every network adapter chipset available on the market. VMware ESXi Embedded, in particular, has a very strict list of supported hardware platforms. Although these
hardware restrictions do limit the options for deploying a
supported virtual infrastructure, they also ensure the hardware has been tested and will work as expected when used with ESX/ESXi.
Although not every vendor or white-box configuration can play host to ESX/ESXi, the list of supported hardware platforms continues to grow and change as VMware tests newer models from more vendors. You can check for hardware compatibility using the searchable Hardware Compatibility List (HCL) available on VMware's website at www.vmware.com/resources/compatibility/search.php. A quick search returns dozens of systems from major vendors such as HewlettPackard (HP), IBM, Sun Microsystems, and Dell. For example, at the time of this writing, searching the HCL for HP returned 129 different server models, including blades and traditional rack-mount servers. Within the major vendors, it is generally not too difficult to find a tested and supported platform upon which to run ESX/ESXi.
Finding a supported server is only the first step. It's also important to find the right server-the server that strikes the correct balance of capacity and affordability. Do you use larger servers, such as a server that supports up to four physical CPUs and 128GB of RAM? Or would smaller servers, such as a server that supports dual physical CPUs and 64GB of RAM, be a better choice? There is a point of diminishing returns when it comes to adding more physical CPUs and more RAM to a server. Once you pass the point of diminishing returns, the servers get more and more expensive to acquire and support, but the number of virtual machines the servers can host doesn't increase enough to offset the increase in cost. The challenge, therefore, is finding server models that provide enough expansion for growth and then fitting them with the right amount of resources to meet your needs.
Fortunately, a deeper look into the server models available from a specific vendor, such as HP, reveals server models of all types and sizes, including the following:
• Half-height C-class blades, such as the BL460c and BL465c
• Full-height C-class blades, such as the BL685c
• Dual-socket 1U servers, such as the DL360
• Dual-socket 2U servers, such as the DL380 and the DL385
• Quad-socket 4U servers, such as the DL580 and DL585
Which server is the right server? The answer to that question depends on many factors. The number of CPU cores is often used as a determining factor, but you should also be sure to consider the total number of RAM slots. A higher number of RAM slots means that you can use lower-cost, lower-density RAM modules and still reach high memory configurations. You should also consider server expansion options, such as the number of available Peripheral Component Interconnect (PCI) or Peripheral Component Interconnect Express (PCIe) buses, expansion slots, and the types of expansion cards supported in the server.