Keyboard, video and monitor switches have been around for many years and can help clear out the clutter on equipment racks in your server room. But these switches have their limitations: You need to locate them near your servers, and their rat's nest of proprietary connector cables consumes lots of space.
Avocent has a better idea, with the first digital KVM switch, called the DS1800. Avocent's switch has no monitor output. Instead, you connect it to your Ethernet network and operate your computers remotely via a piece of software over a TCP/IP network.
It sounds like a great idea. In practice, however, we found the implementation lacking. Considering the high price tag of the product ($10,000), the fact that you still need almost the same number of proprietary cables to connect your computers and poor software execution, the DS1800 isn't yet ready for enterprise users. We recommend waiting until the vendor at least improves its control software before trying the DS1800.
Apart from the freedom of location, there isn't much of an advantage over an ordinary analog KVM switch. The cost of an analog switch is much less - you can buy a great analog KVM for $1,000 and a perfectly adequate one for several hundred dollars.
The advantage of a digital switch is freedom from being near the computer you want to operate, as you could control a machine over the Internet from any location around the world. And by eliminating the monitor connection, you can manage your computers in logical groups around your company, rather than having to gather your staff together in a single "mission control" room.
Both digital and analog KVM switches allow you to view the entire boot process of your servers. This is because there isn't any software installed on the server, unlike remote control products such as Symantec's pcAnywhere. One advantage the DS1800 has over analog KVM switches is it can control anything running on an Intel machine - including Linux or Solaris, for example.
One of the niftier features of the DS1800 is that it gives you a choice of several different sets of cables to connect to your servers. There is one set for ordinary PS/2 keyboards and mice,another for USB connections, and two sets of cables for Sun workstations, which we didn't test. There is no support for Macintosh servers. You choose the configuration when you order a unit, and the cables are included in the price tag.
Like pcAnywhere, software needs to be loaded on the machine you'd like to monitor your servers from: three different programs, in fact. Two of them handle the access control for the switch. You can set things up so that only certain Windows NT or 2000domain users have the ability to control particular computers. The third piece of software is remote control software that communicates with the switch over your IP network, and this needs to be installed on every machine you want to monitor your serverss from.
The first two programs (access control) only need to be loaded on one machine on your network. But the catch is that these programs must be loaded on a machine that is part of your immediate LAN and inside your firewall. The reason for this is these programs need to communicate with your domain server to provide the authentication services. This has one big limitation: You can't control machines across the Internet unless you provide some sort of VPN or tunnel between the location of your switch and the monitoring machine. This is because most corporate firewalls block access to remote users logging on to to their domain controllers over the Internet, as it should be for security reasons.
Quirky mouse control
We had trouble with the DS1800 both at our labs and when we brought it into our ISP's server room. It was simple to switch sessions among the controlled computers: You merely bring up the Windows-based DSView program and click on the computer you wish to control. But we were vexed by the lack of control over the mouse. With each computer we connected the switch to we had to make slight adjustments, depending on the operating system, machine speed and mouse hardware.
Ideally, you'd like the local mouse movements to be synchronized with the mouse movements displayed on the screen of the remote computer -- this is how pcAnywhere works. But this was extremely hard to accomplish, and we spent most of our time on technical support calls trying to resolve this. There seems to be no real systematic way to adjust mouse synchronization other than to try a series of commands on both the Avocent DSView software and try adjusting the remote mouse control panels on each server machine to produce the best results. With one machine we had to replace the Logitech mouse drivers with Microsoft PS/2 drivers on the remote servers. With another, we couldn't really get them working at all. At an ISP with hundreds of machines, this could quickly get tiresome.
Indeed, the mouse control paled when compared with pcAnywhere, which is much crisper and more precise at synchronizing mouse movements. Bringing up remote NT's network monitor or computer management consoles was frustrating with the DS1800 when we tried to move the mouse to various panels around the screen, but there are no such problems with pcAnywhere.
We also had trouble with one 750-MHz Pentium III machine with mixed Universal Serial Bus (USB) and PS/2 ports, and an IBM NetVista that had only USB ports.
Avocent says it is working on better mouse support. Until it does, we recommend steering clear of the product. You can purchase multiple copies of pcAnywhere or buy an analog KVM switch for a tenth of the price.
This story, "Flaws mar digital keyboard, video, monitor switch" was originally published by NetworkWorld.