So you need to purchase a KVM switch for your SMB? As mentioned in my earlier blog on the introduction of some new IP KVM models by ATEN, there are many situations where a KVM switch is the most efficient and desirable method to operate and maintain a bank of servers.
Now, I'm certainly not saying that getting a KVM switch is necessary for all SMBs. But if your organization does require the use of one, what are some of the important features that the budget-conscious SMB should look out for? To help you along, I've created a short list of the most desirable features from an operational point of view.
If you've ever wondered about the price difference between lower-end KVM switches and those that cost significantly more, the likelihood is that the more expensive models are IP-enabled. In its simplest form, an IP KVM will allow an administrator from a remote workstation to connect through the network using its own proprietary client software. Indeed, most non-basic KVM switches nowadays are IP-enabled.
Note that the standard risks and advantages of being network-aware apply here. For one, an additional door is now present from which a hacker could conceivably break in. With the correct network set up though, it is also possible now for an administrator to access the IP KVM from home or locations far away from the data center.
Number of concurrent users
This feature might appear confusing initially, but is actually quite simple. Consider the fact that KVMs can connect anywhere from a dozen to over 100 computers. It would be ludicrous if only one administrator at a time could log in to perform maintenance work or check on the servers. As such, mid-end and higher KVM models have support for at least one "local" user and another "remote" user. Local access refers to the keyboard/display/mouse combo directly connected to the KVM, while remote users would be those connecting via an IP-network.
Higher-end KVMs support two to three, or even more, simultaneous remote users. Note that KVMs offering just one remote and one local user might not mean that these two users are able to do concurrent tasks simultaneous. Obviously, what works best depends on the needs of your SMB. However, I would advocate support for at least one remote and one concurrent local user in instances where more than a dozen servers are connected via a KVM.
CAT 5 cabling
Lower-end KVMs tend to depend on either proprietary cables or just a bunch of PS/2 and VGA connectors joined into a single cable. The downside is that these cables are often expensive, as well as being limited to between five to seven meters in length. They are also woefully inadequate when there is a need to manage servers that are spread across a few racks. Fortunately, higher-end models use either STP or even CAT 5 UTP cables that allow KVMs to greatly increase their physical reach.
Ability to cascade
SMBs planning for an increase in their server count will want a KVM model that supports cascading. What this means is that more than one of these appliances can be stacked together for seamless access to all the connected computers. Note that the connectors for these KVMs are typically proprietary and support cascading only with the same models or devices within the same product family.
It should be made clear that the above list isn't an exhaustive one - not by a long shot. At least one key consideration - usability - simply cannot be meaningfully explored in a discussion centered on technical specifications and features. Indeed, a high-performance graphics engine and superior compression algorithm can result in a much smoother experience to greatly enhance productivity. And overriding this would be a KVM's reliability when faced with the rigors of 24/7 operation.
However, I hope the above will be adequate to get you started on your road to acquiring or evaluating a KVM switch.