The Uninterruptible Power Supply (UPS) has long been the Rodney Dangerfield of the computing world, but it's finally getting the respect it deserves--and for a variety of reasons. Distributed client/server systems now run many of the mission-critical applications that were once entrusted only to mainframes. These networked systems carry far more risk of power problems than their mainframe cousins--power problems that can cause costly downtime, loss of data, and equipment failure.
According to a five-year study conducted by the National Power Laboratory, the typical North American computer site experiences nearly 300 significant power disturbances each year. A recent study by Contingency Planning Research, Inc. reveals that nearly 50% of all lost data at computer sites is caused not by faulty hardware or software, but by power problems, such as surges, spikes, brownouts, and utility failures.
And the clincher? About two-thirds of the servers in operation today have no UPS protection at all. "Most market studies say that the server market is only 25% to 35% penetrated by UPS products," Doug Milner, Exide Electronics' director of product marketing, said. "It's imperative to protect the mission-critical applications on these servers, and it's equally important to tie the UPSs into a network-wide solution. Yet, you'd be surprised by the number of companies that aren't doing these things. I recently visited a civil engineering firm with 25 servers that weren't UPS-protected. When the weather was bad, they'd send 10 engineers scurrying around the building to shut down the servers."
Some companies do an admirable job of providing backup power in corporate headquarters but fail to adequately protect the communications devices linking them to remote systems. "File servers are of little use to anyone if the communications links that access them experience problems," said Wes Tazzia, marketing director for Controlled Power Company. "The only way to stop a power disturbance from disrupting a network is to put power protection on all current-carrying pathways into the network and to put a UPS between any two pieces of equipment connected via a communications line that is plugged into two different AC sources."
If your system is unprotected, you're taking a very big gamble. "Without the ability to do a graceful shutdown, you can really mess up your \[Windows\] NT system," according to Vincent Giordano, PowerChute product manager for American Power Conversion (APC).
A terse definition of a "graceful" shutdown in the NT world is: File systems must be correctly shut down, including NT File System (NTFS). Do you have enough backup time to do that--while still maintaining power to every hub, bridge, and router between your server and workstations?
UPS Market Trends
Before I discuss the more technical criteria for selecting UPS hardware and software, let's look at some of the general requirements for most UPSs today: outstanding price/performance, simple installation/configuration, and rack-mount capabilities to save space.
The UPS market is aggressive, and the vendors cited in the directory are locked in some fierce price/performance battles. The UPS power ratings (expressed in VA--volt amperes--or kVA--kilovolt amperes) are climbing while prices are falling. Units can cost anywhere from $100 to many thousands of dollars, depending on their capacity. Once you determine your power needs, you can shop around to get a good price. However, remember that sometimes a higher price tag is justified if the unit boosts productivity because it has superior network power management. The savings can be sizable when a single network administrator does the work of 10 scurrying engineers; then multiply that amount by the number of major outages you experience in a year.
Usually, UPS products are easy to install and configure. Sometimes, however, the hardware doesn't come fully assembled, so you might want to check with the vendor before you purchase a unit. "Our customers want to know that they can take the unit out of the box, plug it in, and walk away," Michael Miga, Superior Electric's marketing manager, said.
Because saving space is a key consideration at many sites, many UPS vendors offer rack-mountable versions that can be installed in a wiring closet. "Some of our customers really appreciate the convenience of having the UPS and all the internetworking gear \[together\] in one convenient place," commented Marc Vernon, Tripp Lite's marketing communications manager.
Hardware Issues
In the NT world, a UPS product must deliver not just reliable backup power in the event of a blackout, but clean, steady power around the clock to prevent data loss and equipment failure. That's why you should narrow your choice to either on-line or line-interactive UPS products. Most on-line UPSs provide what's called dual-source power to continuously condition and correct the incoming power. They take AC from the wall, convert it to DC, regulate it, and then convert it back to AC power.
If you experience a total blackout, most UPSs deliver from five to 20 minutes of full-load backup time for system shutdown. You need to be aware of how much equipment you are running off the UPS. A 2kVA UPS, for example, should be able to handle about four medium-sized Intel 486 servers, depending on the number of peripherals, display sizes, etc. If you need more time--a longer safety buffer--you can get extended-run backup with add-on battery packs.
Most UPS units come with two-year warranties, and the batteries can sometimes last far longer than that. (For instance, the batteries in many on-line UPSs often last five to six years.) Eventually, however, they wear out and must be replaced. Many units contain hot-swappable, user-replaceable batteries that can be changed without powering down the connected load. In Europe and 14 states in the US, user-replaceable batteries will soon be mandatory to eliminate the environmental hazards of dumping worn-out UPS units without proper battery disposal. The majority of UPS models also do self-diagnostic tests on a regular basis and can be continuously monitored with network software.
Simple Network Management Protocol (SNMP) support is another key consideration. Some vendors offer an SNMP interface card that plugs into the back of the UPS and connects it physically to the network so it can be managed via SNMP.
Scaleability is another important consideration. You should be able to upgrade your UPS's power rating with firmware (say, from 600VA to 800VA by adding a battery unit) instead of having to purchase replacement hardware.
You can also find UPS hardware that supports multiple voltages. "Our Matrix-UPS model does 208V and 120V simultaneously," said Ray DeSabato, APC's Smart-UPS business unit manager. "So if you have a server requiring 120V and an AS/400 needing 208V, you can see some savings."
You should also be concerned with the time required to switch from line power to battery backup. If the switch isn't fast enough, then the UPS does no good because your computer will crash before it can get to the battery. On-line models solve this problem by supplementing line power with battery power constantly, so there is no lag time.
Do You Need Special Software?
One of the major debates in the UPS industry is whether NT, out of the box, offers enough shutdown capabilities to make additional software unnecessary. Some UPS vendors have gone far beyond NT's built-in shutdown features to deliver more sophisticated, network-wide power-management capabilities. The hallmark of these packages is their ability to monitor network power conditions in real-time from a single console. They can often spot emerging problems long before shutdown is necessary.
Many of the high-end packages also monitor UNIX and NetWare systems. "Our customers require interoperability because they typically have a common network backbone and then run multiple network operating systems for various applications," Milner said. "For example, the engineering department may be doing design work on SPARC workstations, the finance department may be running Digital Alpha servers to do general ledger consolidation, and there are often NT or NetWare systems running, too. They all run on the same corporate network. That's why our OnliNet software interoperates with itself on Windows NT, NetWare, and UNIX systems."
Not all UPS companies take the same approach, however. "We're taking a wait-and-see attitude about the NT market to see if there's a real demand for our own power-monitoring software," said David Fencl, Oneac's marketing manager. "The shutdown features built into NT are pretty good, and they may satisfy our customers' needs." Sola product manager Steven Cosgrove disagrees: "For systems requiring less than 2kVA of backup power (and the majority of NT sites fall into this category), our customers are much more concerned with interface software than with the details of hardware design."
So, because the days of "dumb" UPSs--those that are nothing more than big batteries--are over, the logical question is, "What level of administration do you need?" This issue can be complicated, depending on your requirements for interactivity, reliability, etc. Windows NT provides minimal, yet workable, UPS management functions. The UPS Service on the Control Panel (see screens 1 and 2) offers shutdown and user-notification parameters, UPS configuration, timing, communications port settings, and a command file to tell the computer what to do in the event of a power failure. But is this enough? Let's look at who needs additional functionality and why.
Systems administrators in charge of servers and casual users' machines need real-time remote querying and manipulation/control of network server and workstation power units. This includes being able to decide what to do if an application is still running at system shutdown time--Should it hang? Should it crash? Can it be shut down in an orderly fashion?--automatic shutdown procedures, who should be notified and under what circumstances, and which situations are worth worrying about (such as power/unit status--fluctuations, test results, etc.--see screens 3 and 4 on ). End users, such as engineers and programmers dealing with critical data, should be able to know the condition and load status of their UPSs, so that when an actual power failure occurs, their systems are not adversely affected.
Exactly what do these various users need to know, and what issues should they be concerned with? Put "Check condition of battery" at the top of your list.
What condition is your battery really in? Suppose your power goes out for the first time in two years. Even if you have a UPS, it's probably never been tested in a live situation. Suddenly, your uninterruptible power supply has been interrupted. Everything you were trying to protect has been clobbered, and you don't know why. That's where administration software comes in--something to handle self-testing of your UPS's battery integrity and reliability. A number of power supply companies (see the sidebar "UPS Management Software") have used NT's UPS Service--a handy tool that communicates with your UPS via your serial port--to build better interfaces and management packages for their units. Thus, these companies can provide you with routines to schedule regular tests of your battery's condition, calculate load factors, and monitor environmental conditions--things that NT can't do by itself. The results of these tests can be passed on to the user or the administrator via event logs, SNMP, email, on-screen messaging, or even direct paging and dial-up-at-home notification.
Some other features you'd probably rather not do without are:
- Customizable command files
- Modifiable user messages
- Real-time graphical view of UPS status
- UPS power events log
- Display of power analysis by time of day
- Ability to broadcast messages only to users logged on to the local server
APC's PowerChute Plus software also works with Microsoft Systems Management Server (SMS). "When you load PowerChute, your PowerChute NT server is available on your SMS chart," Giordano said. "It's all integrated."
As you compare software packages, there are also some advanced features to consider:
- Security features: Some power-monitoring software can detect unauthorized computer usage or unusual data transfer out of a server. If security is breached, the software automatically powers down those devices. You can also automate a system shutdown/startup routine to reduce power consumption during off-peak business hours and prevent unauthorized access.
- Identical support for all servers: You can find power-management software that runs on Intel, Alpha, PowerPC, and MIPS servers, right out of the box.
- SNMP extras: The SNMP agent must reside near the server. Since NT is a proxy agent, some vendors have written code that sits on top of the power-management software to allow the network management station (NMS) to see the UPS through the server. For a small additional charge, you can gracefully shut down the system, plus see the UPS from the NMS.
- Greater messaging/notification features: Some software packages provide a wealth of options for spreading the word about network power problems, including the ability to page the administrator and notify server users only.
- Environmental monitoring: A handful of vendors offer UPS models that can remotely monitor temperature, humidity, smoke, fire, and other environmental conditions that could cause an unforeseen shutdown.
There are also several vendors that offer power-monitoring software, such as PowerMon II from System Enhancements, Inc., that lets you take advantage of the power-management features already found in NT. The following are some of the capabilities to look for.
- Use of NT's Named Pipes to provide remote UPS monitoring and shutdown configuration (This enables any workstation or server to be a UPS management console.)
- Integration with NT's Performance Monitor to allow viewing of UPS statistics, such as power quality, from within Performance Monitor
- Reporting alarm events to NT's Event Viewer
If you feel that NT's built-in capabilities are enough for you, all you need from your vendor is a serial-port cable. You're in business!
A New Role for the UPS
For most of computing history, the UPS has been a "dumb" product that existed solely to condition incoming AC power and safeguard backup power. Now, UPS products are playing a vital role in network management. They can graphically monitor voltage in real-time, prevent unauthorized server usage, gracefully choreograph remote shutdowns, and even notify network administrators by pager.
UPS products can safeguard the availability of your NT-based applications--many of which are the life-blood of your business. "The move we're seeing toward remote, distributed networks requires enhanced UPS manageability," John Page, Hewlett-Packard's UPS program manager, said. "A glorified surge suppressor is no longer adequate for protecting these networked systems."
