Blade Server technology

What is a Blade Server?
Blade Server’s are high density, small foot print servers that are housed in centralized chassis; that have common power, cooling and management. They also share common Ethernet, fibre and other industry standard data communication paths with all the other blades in the chassis.

The blade chassis can hold several blade servers in a multiple U package verses the traditional 1U server architecture. A U or Rack Unit is defined as a measurement of height for mounting in a server rack which should equal 1.75inches. Blade server manufacturers look to maximise the blade density by following the formula (server/U) >1. Blade servers make it possible to increase server packaging density and eliminate some of the problems inherent in 1U servers.

These problems include excessive cables, difficulty in servicing, complex connections for input/output (I/O) devices and systems management and when many 1U servers are assembled in a rack, the repetitive use of hardware components such as optical media, fans, and power supplies.There is a lot to be said about the advancements due to superior server density. Blade servers provide up to 50 percent improvement compared to traditional tower or rack mounted servers with regard to size, surface area and footprint.Blade servers simplify cabling requirements and reduce wiring by up to 70 percent. All cabling, operator wiring (keyboard, mouse, etc.) and communications cabling (Ethernet, Storage Area Network (SAN) connections and cluster connection) are greatly reduced. Also using blades reduces the number of power cables needed in an environment, as power cables are reduced to eight (on average) from eighty.

Some points for consideration when choosing blade servers is cooling and power requirements. Blade centers offer smarter power and cooling architectures. This combined with the smart use of energy efficient components, such as low voltage processors will allow Blade Server users to extract the most performance from every kilowatt. But in the majority of the world’s data centers, 63 per cent of a datacentre’s power consumption is associated not with IT systems themselves, but with cooling the IT equipment.

Blade chassis and blades are very modular by design. Switch modules, power modules and fan blower modules, management modules to be removed autonomously and replaced quickly without the use of any major tools. Since all major components plug to a single mid-plane, there are no buried components, as there are in many standard servers, and no internal cabling that can be overwhelming to an untrained end user.

Hard disk and tape storage subsystems can be inside the blade chassis or external to the chassis. Blade servers can be disk-less since they can boot from external storage in a SAN. This configuration can increase reliability and reduce space requirements by partitioning storage resources in one centralized location and computing resources in another. This also eliminates storage redundancies and simplifies storage management. There are many storage connection methods (e.g. FireWire, SATA, SCSI, DAS, Fiber Channel, Infiniband and iSCSI) all which can be internal to the blade chassis or as an external connection with appropriate switch module(s).

Blade Chassis manufacturers offer centralised management of their products and this may be Hardware or Software based. Management software enables server administrators to deploy, control and monitor server resources from a centralised administration console depending upon the manufacturer. Software management tools simplify the management and reporting functions for blade servers. These products include HP’s Systems Insight Manager.

Another feature of blade servers is virtualisation. See the virtualisation article for the Journal April 2008 to get further details on virtualisation. Some of the major virtualisation providers are: VMWare ESX, Citrix XenServer or Microsoft Hyper-V. Virtualization is the method by which “guest operating systems are run under another host operating system, with little or no modification of the guest OS”. This virtualisation allows multiple OSs to operate on a single hardware platform thus consolidating servers. Virtualisation helps to reduce energy costs to clients.

And as energy prices rise to nearly 27 cents per kilowatt hour in the Cayman Islands, businesses can save hundreds, thousands or even millions of dollars in energy costs each year depending on the size of their datacenter by upgrading their architecture to blade technology. A blade chassis filled with blades provides the least expensive total cost of ownership (TCO) in terms of power consumption based on multiple year usage. Rack servers, compared with the components in the blade server and a fully loaded blade server, consume more power, and this adds to their infrastructure expenditures over a five-year lifespan of the technology.

Blade servers reduce but don’t eliminate redundant hardware components requiring electrical power, a pivotal consideration in TCO. While rack-able servers are less expensive than blades when buying only one or two servers, because you have to factor in the cost of the blade chassis, a fully configured blade chassis is the more economical hardware buy than purchasing the same number of rack-able servers.

Blade servers’ drawbacks still prevent their adoption for some applications, such as those requiring large amounts of on-board, indeterminate storage expansion. In addition, a data centre using blades is captive to the vendors’ business partners to supply such devices as SAN’s, Fiber switches or Ethernet switches, because these must be housed inside the blade chassis. This is fine if the vendor is competent, spares are available, and the chosen technology components mesh with current and proposed network operations center (NOC) gear. If all works with little orchestration, costs will remain low.

Blade servers provide a comprehensive solution for data centres requiring flexible, high-density deployment and management of high performance servers. “Blade servers can pack more server performance into less space while reducing cost and complexity, simplifying deployment and management, and improving overall data center performance”.

There are just a few select vendors here on Grand Cayman that can offer complete Blade Solutions in a turnkey operation…Kirkiss is one of those vendors.

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