A blade server is a compact computer server, designed to work together with a blade or server rack. A computer server is a computer designed to provide services and support to multiple users in a network. Each individual blade is a tightly compressed computer processing unit. The blades are designed to work with the rack, as they do not have their own power, cooling or protective covers.
A blade rack looks just like a metal bookcase. The blades can be inserted horizontally or vertically, depending on the design selected for the rack. All power and network cables are connected to the rack, and not the individual blades. This is due to the built-in connectors that fit exactly into the back of the blade server. Many racks have a glass front door to keep out the dust and have powerful cooling fans built into the top and bottom.
These fans are used to keep the temperature at the appropriate level for all the blade servers. Blade racks are usually stored in a server room, which has built-in cooling capacity, a dedicated power source and air filters. A blade server has three components: memory, processor and storage capacity. All additional items, such as hard drives, fans, power cables, etc., are removed and are built into the rack or a separate location. This shift in design vastly decreases the space required, allowing the same space to support a larger computer processing capacity.
Cooling is a major concern for blade servers. The first generation blade servers would exceed the cooling capacity of a standard server room with the blade racks at 50 percent capacity. The need to build space around each unit for air circulation reduced the space-saving capacity of these units. Modern blades have a better design and a standard rack can hold up to 128 blade servers at one time.
Another benefit of a blade set-up is the increased efficiency of the network. Inside the rack, all the blades are connected to one or more network buses. This reduces the overall costs, as there is no need for a one-to-one relationship between the server and the network bus.
The storage issues for a blade server set-up are solved with the use of external storage services and alternative connections. This functionally allows the hard drives to be stored in a different location. In an enterprise size set-up, a storage area network, or SAN, is created to manage all the data and application software. This resource is accessed using dedicated network connections and can actually enhance system performance.