The Rack Mounted Server Platform
The standard computer server-rack platform form factor uses 1U units, which have the following minimum dimensions 19" (482.6 mm) wide and 1.75" (44.45 mm) tall.
The most common computer rack server platform form factor uses a 42U configuration which means that each rack is capable of containing a maximum of 42 x 1U units. At the most this means a grand total of 42 rack mounted server computers.
Unfortunately not many self-contained servers can be accommodated into a mere 1.75” (44.45 mm) height form factor. Thus most installations will fall considerably short of the maximum 42 units especially when a monitor is included. Still the rack does make a good secure enclosure for multiple servers.
The 1U minimum unit size applies to all units that are to be mounted into the rack including servers, redundant power supplies, networking devices etc. Units that are multiples of the 1U form factor dimensions can be accommodated but smaller units generally can not (at least not without additional mounting braces).
Other features added to the rack mounted server platform and/or the rack to facillitate their use in a rack-mount scenario include:
Sliding Rails - The addition of slide rails allowing the equipment to be slide in and out without disconnecting it from the rack chasis is an added security feature. This gets even better when the slide rails can be locked in both the in and out positions. This gives added stability and reduces accidental dropage during routine service.
Server Mounted Locking Pins - This little extra enables the server unit to be “dropped” into place without necessitating fiddling with screws. This one is a big favorite with administrators for obvious reasons.
Rear Mounted Handles - Great for pulling and pushing servers in and out of the rack chasis. It certainly saves a lot of cable pulling and the ensueing damage that causes.
Rear Mounted Cable Tray - Somewhere to tuck cables neatly out of the way. Not only does this help prevent “cable knotting” but it also gives the added protection of securing cables against accidental displacement. In combination with lockable sliding rails the rear mounted cable tray enables the server equipment to be still operational while it is extended out of the frame. A must for “hot swappable” devices.
Indicator Lights - Identification lights on the front and back of the rack to identify individual rack mounted devices. It can be very difficult to identify which machine you were working on at the front when you go to the back of a fully loaded rack.
Here is yet another reason why a proper naming convention in combination with a secure labeling system is so essential in these situations. For more information see these articles, Building Your Own Naming Convention and Making Your Own Indexed Labeling System.
KVM Switch Support - Including a KVM switch with the rack means that an administrator can directly interact with any server mounted in the rack using just one keyboard, mouse and monitor that can be shared by all members of the rack.
Standard rack mounted servers can generally exist outside of the rack and function within a network environment with just the addition of a power cord and appropriate network cable.
The Blade Computing Server Platform
Blade servers are self-contained computer servers, designed for high density implementations. Unlike the bastion host or standard rack mounted servers the blade computing model has units with a number of hardware and support systems removed. The blade chasis provides these functions rather than having each individual blade component do them.
This has resulted in blades that are specialized for processing, network, storage, Input/Output (I/O) and memory subsystems. “A blade for every function”. This is the phrase that comes to mind.
If you need more processing power then add a blade that is loaded with multiple multi-core CPUs and oh-la-la, more processing power to brag about is yours. Similarly if it's more memory for those graphics rendering intensive applications that you require, then add a memory blade. You can even get “general purpose” blades.
The idea behind this is that removing these components saves considerable space. In addition the removal of the power supply units (PSU) not only saves considerable space it also reduces the overall thermal energy produced during normal and stress level operating conditions.
Everyone who has put their hand at the back of their PC is only too well aware of the amount of heat that the PSU generates. Factor in the fact that the PSU is the most common component of all computers to fail and you see the sense in replacing thirty or forty cheaper PSUs with two to four more robust and reliable units. In the big picture perspective this actually is cheaper than the former solution.
By removing it and replacing each blade with a dedicated lead from a DC providing higher quality less failure-prone redundant set of PSUs considerable energy and accrued downtime losses are saved.
The big thing in blade computing is the engineering technologies encompassed by the blade enclosure. This is what makes it all possible. Here are some of the support features that the blade enclosure delivers:
- Housing for multiple blade servers
- Provision of utility services such as power and cooling
- Provision of infrastructure such as networking and various interconnects
- Platform Management
Different manufacturers do have different ideas of what should be included with each blade as well as what should or should not be provided with the blade enclosure. However, it is all of these elements in combination that make the blade computing platform. The benefits of the blade computing platform include:
Minimum Size Limit Restrictions Removed - Removal of the 1U minimum size limit requirement with the traditional rack mounted server platform.
Higher Unit Densities - Instead of the 42 unit maximum of the standard rack it is not unusual for blade systems to hold up to 100 or more individual blade units per blade enclosure.
Specialization - This is also due to the size reduction that blade unit specialization introduces and will no doubt escalate as technology, integration and miniturisation continue to evolve.
Improved Energy Efficiency - The “green IT” movement is becoming an ever increasing influence in technology today and will undoubtedly continue to do so in the future.
Additional Information - Check out ServerWatch.com if you would like to find out more about various specialty servers and new developments in the server industry.
