Rack Servers

If you anticipate the need to run several servers, either right away or in short order, consider moving up to rack-mount models. These types of servers come in a standard width (to fit in a 19-inch rack) and a standard height (a multiple of 1.75 inches, or 1U; a standard rack is 42U high). A rack permits you to fit many servers into a relatively small footprint, and typically it includes a cable-management system to keep your installation neat.Computer-Hardware

Most rack servers are highly expandable, with sockets for multiple CPUs, copious amounts of memory, and lots of storage. Rack-server systems are highly scalable, too; once you have the rack in place, you won’t need floor space for additional servers until the rack is full. Although they typically cost more than tower servers, they’re cheaper than blades.

Since rack servers operate in very close proximity to one another, they require more active cooling than tower servers do. The fans in these servers can be quite loud, and you’ll need a climate-control system to keep a full rack cool. For those reasons, most businesses isolate their rack servers in a dedicated room. Rack servers can be more difficult to maintain, because they must be physically pulled from the rack for servicing. And like a tower server, rack servers require a KVM arrangement for setup and management.

Blade Servers

The primary distinction between a rack server and a blade server is that several blade servers operate inside a chassis. Adding a new server is as simple as sliding a new blade into the chassis. You can install other network components, such as ethernet switches, firewalls, and load balancers, alongside the servers in the same enclosure, and you can install the whole assembly in a rack. Since the chassis provides the power, cooling, input-output, and connectivity for all the devices inside it, you don’t have to deal with new cables when you add something. Blades are neater and can pack more computer power into a given space than any other server ecosystem, yet their upfront cost is higher because you must also purchase the enclosure.

Blade servers do have their drawbacks. Typically they provide fewer expansion opportunities because they aren’t equipped with as many PCIe slots and drive bays as tower or rack servers are. On the other hand, businesses deploying blade servers usually have shared storage, such as a storage area network, to support their blade servers (and some blade chassis can accommodate SAN storage right alongside the servers). As you’ve probably guessed, housing all those components in such close proximity generates a lot of heat. Blade systems, like rack servers, require plenty of active cooling (usually augmented by fans mounted inside the chassis).

The Bottom Line

If all you’re looking for in a server is file sharing, client backup, and limited remote-access capabilities for a small number of employees using computers (ten or fewer), a Windows Home Server machine or a NAS will satisfy your requirements with an extremely modest investment. A larger small business that needs just one or two more-powerful servers would be better off with towers. They don’t take up a lot of floor space, and they don’t require elaborate cooling systems, but they’re easily expanded, and high-end models can support virtualization.

Once your IT requirements grow beyond what a couple of servers can do, it’s time to consider moving up to a rack server. Dozens of these machines can fit in the same footprint as a couple of towers, and this server architecture is quite scalable. Blade servers are even more space-efficient and scalable. If you need more servers than will fit in a rack, you’ll be happier with a blade ecosystem.