As our servers rooms get larger and more complex, maintaining power in cases of interruption becomes even more important. Our past reviews of UPS units have mostly been aimed at the single server or workstation platforms, with a maximum of 1.5kVA. Two years ago we looked at TrippLite’s SmartPro 2200RM 2.2kVA UPS and were mightly impressed (to the point that we bought the review units). Larger UPSs than these tend to be unwieldy, expensive contraptions, mostly designed for datacenters and corporate server rooms. What about those of use with a few servers in one location? Do we need to use separate UPSs for each? TrippLite has once again come through, lending us one of their new Smart Unison 6kVA UPS units.

The Smart Unison 6K is an impressive box, about two feet tall, one foot wide, and two and a half feet deep. It’s a largish box compared to the usual UPSs we deal with. It’s also heavy, tipping our scales at 350 pounds. As shipped, the Smart Unison 6K is bolted to a pallet and needs two strong people (or a fork lift) to move it around. The box is attractively styled, however, looking quite artistic from the front. Once maneuvered into position in our server room, we started to appreciate the benefits of this type of larger UPS right away.

The Smart Unison 6K is connected to a 240V wall socket, ideally dedicated to the UPS itself. The input is hardwired through a break-out box and is plugged into a standard 240V sockets, and takes anything from 208 to 240V, 30A service. Most electrical panels will be able to deliver this supply from an inexpensive breaker. The outputs are hard-wired to a break-out box, too, in combinations of 120 and 240V sockets. Three serial ports on the Smart Unison 6K can be connected to three different servers, all running TrippLite’s PowerAlert software. The Smart Unison 6K is SNMP-compatible with an add-in board, and boards allow direct connection to Ethernet networks, too. (For the record, TrippLite provides $100,000 lifetime damage warranty for connected devices. Even better: there’s no need to mail in warranty cards!) The front panel has LEDs to show constant conditions, although most users will likely rely on the PowerAlert software.

Connecting the Smart Unison 6K took us a couple of hours, simply because of the size of the box and the need to physically manhandle it into position. The process of installing and connecting was simple and easy, except for the grunts and groans of the moving staff! There are a number of features we noted right away about the Smart Unison 6K. The first is a bypass capability that lets you switch the UPS out of the circuit for maintenance, testing, or other purposes. If damage ever occurs to the UPS itself, this circuit is activated automatically and connected equipment is fed pure incoming power. The output voltage can be user selectable between pure sine waves, or four different levels of line-interactive behavior. The internal battery can be hot-swapped, and external batteries can be added for additional protection.

One feature we really like is a cold-start function. Most UPSs, when they are shut down in the absence of line current, cannot be restarted. The Smart Unison 6K can be started from the batteries themselves, even when no power is available. This feature may not sound useful but anyone who has lived through extended power blackouts and needed to boot a computer for a free minutes will appreciate it no end.

The Smart Unison 6K can be controlled through the network (using the plug-in SNMP card) or through any of the three serial ports. The ability to hook three servers up to the Smart Unison 6K is handy as it allows all three to detected power problems and take corrective action without relying on SNMP or other network broadcasts. We used the Smart Unison 6K with TrippLite’s excellent PowerAlert software, first with the shipping 10.1 version and then with a beta of 10.2. There are a number of features with PowerAlert that endear the software to any administrator, not least the fact that it can control practically any UPSs on a network (drivers for non-TrippLite UPSs are available on CD and on the TrippLite Web site). And while some UPS manufacturers charge for the management software, PowerAlert is supplied free.

Version 10.2 of PowerAlert shows off some slick tricks including a visual view of all UPSs on the network in much the same representation as expensive network management software does. Each UPS can be managed from the interface, and groups of UPSs can be created and manipulated at will. Any change in the state of a UPS shows up as a color change on the PowerAlert screen.

The Smart Unison 6K provides constant regulated power to all connected devices. Our test meters showed pure sine waves to all output (120 and 240V) connectors, even when we did our usual nasty tricks with the incoming power supply. All of our spikes and brownouts were handled with aplomb, even with the Smart Unison 6K loaded with 6kVA. RFI filtering was excellent. We measured exactly 6kVA and 4200W output. When we failed the incoming power, the Smart Unison 6K kicked in instantly (as expected). With full power load (6kVA) the Smart Unison 6K lasted twelve minutes on battery power. At half load (3kVA) we obtained 31 minutes of full power. On a much smaller load like a single server, we got several hours of battery backup from the Smart Unison 6K. Battery recharge time from drained to measurably full was four hours.

Is the weight and cost of the Smart Unison 6K worth the investment for you? It depends on your server needs. The cost of the Smart Unison 6K is less than four or five equivalent lower power UPSs, and the use of a single UPS makes floor space and maintenance that much easier. Of course, if you are only powering a few hundred watts of equipment, the Smart Unison 6K is overkill. But if you have over 2kVAs to support, e think the Smart Unison 6K is your ideal choice. We’re buying the review unit (again). Oh, and wear back support when you carry yours in.

Smart Unison 6K $5499
Breakout-box $129
1111 W 35th Street
IL 60609
773-869-1329 fax

Summary: As 6kVA UPS behemoths go, this is the best UPS package we’ve tested. Excellent test specs and enough juice for a small server room.