Posted on Thu, Jan 21, 2010 @ 08:33 PM
Today there are a few different choices for server form factors, and buyers need to know how to make the best decision based upon several criteria. Below are some standard server form factor options, along with some information to help you determine which type may best suit your needs.
Tower Servers
Full-size Tower servers are a thing of the past, except for use in very specialized applications. Modern Tower servers are more midsize in height and therefore physically similar to Tower-Style Desktop PCs. The extensibility of Tower servers is limited, and therefore they are best positioned for departmental use, small remote office locations or to serve the needs of small businesses with limited growth projected for server requirements. Choose tower server configurations when cost is a concern, your needs are simple and projected growth is very limited.
Tower Rack-Mount Conversion
These days, the Tower-to-Rack conversion systems are predominantly used in situations where a single server requires a substantial amount of internal storage. These are typically specialized application servers and having the ability to rack mount them is advantageous. Choose this arrangement when you need to dedicate a large amount of storage to either a specialized application server or an independent database server and when your needs for external network and storage connections is limited.
Rack Mount Servers
Rack-mount servers are still the most popular server form factor acquired these days. Standard rack enclosures are 42U in height (1U = 1.75") and can therefore accommodate up to forty-two 1U servers which are often referred to as pizza-box servers. The rack enclosure is typically equipped to integrate and provide power and data cabling as well as for a measure of physical security. Rack enclosures are usually an important component in airflow management toward providing adequate cooling for the server environment.
The popularity of rack-mount servers will likely decrease (eventually) as the benefits of the blade server chassis configuration is well proven. Choose this server form factor when your overall configuration will consist of an average to large number of nodes, and each node is still required to have substantial capacity versus the comparable capacity available in a blade server.
Blade Server Chassis
Blade server chassis are a somewhat newer server form factor that further integrate power and data cabling and achieve greater computing power density in a given space. This increased ratio of computing power per square foot requires additional consideration, as paid to cooling and many early adopters disrespectful of this fact learned a hard lesson in airflow management. It is important to note that blade servers still do not have the internal capacity that rack-mount server do even though four-processor blades are available and further technological advancements in consolidation continue to be made.
The blade server chassis concept has been such a success that Hewlett Packard has designed a smaller chassis designed to accommodate eight or fewer servers in a chassis only 6u in size. IBM has a small chassis that can hold six server blades in a 6U chassis and also include space for a significant amount of shared storage. Additional server manufacturers like DELL and Fujitsu also continue to invest in further refining the blade server form factor. The point is that a reasonable ROI (Return-on-Investment) can be achieved even with these smaller server densities because of the many benefits offered by the blade form factor.
Blade Server Chassis allow us to achieve much greater computing power density in a given space. This design eases management, greatly reduces required cabling, is substantially more efficient with regards to power usage and cooling requirements and achieves a ROI in a realistic period of time. Choose the blade server chassis form factor when each server blade or node can be of a relatively small capacity and when you need to achieve great server densities and scalability. You should also lend strong consideration to the blade server chassis because less infrastructure is simpler to manage.
Hybrid Blade/Rack Grid Chassis
The IBM System x® iDataPlexTM and the Hewlett Packard ProLiant SL Scalable System represent the latest thinking in extremely large scale-out computing. It is reasonable to label these solutions as Hybrids as they seem to blend design aspects of conventional rack-mount servers and blade server chassis design. These systems represent the current state of the art in x86 compute power density. In order to achieve these great densities certain compromises had to be made. For example, each server node typically does not have redundant power. This is acceptable given the intended usage of these machines; web server farms or other cluster aware application usage. In this scenario a single or even a few nodes failing does not halt application availability. In fact, it is claimed that sever density can be increased by more than 200% over conventional rack-mount server designs.
This concept is the newest twist on server form factor and is viewed by some as a combination of conventional rack-mount and blade server chassis designs. This is for a large-scale solution and can assist in solving concerns with constraints in power, cooling and physical space. You should consider these systems if your needs call for truly massive scale-out computing for applications such as Web 2.0, HPC (High-Performance Computing) or very substantial and corporate data processing.
What's Next?
Some people say that the challenge going forward seems to be concerns with rolling out and managing large-scale server deployments. In that regard, Unified Computing seems to be the next frontier, at least according to Cisco and Microsoft. Thanks for reading.
Perry Szarka is the Datacenter Strategic Business Unit leader at MCPc. He works closely with clients to understand their business objectives and discover solutions to help them achieve their goals.
Images courtesy of IBM and Hewlett Packard.