Preventing data loss from power line disturbances

"death can come to your data and hard drive at any moment!"

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Until recently, I operated my consulting engineering practice from an office in a commercial building that also housed a number of other small businesses, consultants and startups. Over the years my business neighbours came and went. Some were in high-tech, medical devices, drug therapy, accounting, investments, security, motor sports marketing, stage production, etc. I became good friends with the principles and employees of many of these companies and when the opportunity presented itself, I would often offer free advise and help in solving their computer and IT problems.

One of the most common instances when I was afforded an opportunity to offer free advise was during and immediately after a power outage. I recall numerous times when we’d have a sudden power surge, then the lights would dim, the building would shake and then everything would be dark. In the quiet aftermath it was easy to hear the profanity echo up and down the hallway as people working in neighbouring offices realized that they had just lost hours of work on a document or an experiment was ruined!

If the outage lasted more than a few minutes people would begin filing out of their offices and inevitably many of them were crowded outside my door. I’m not sure exactly what drew them there. Perhaps it was the mysterious beeping sounds in my office or the eerie glow in an otherwise dark building? Regardless, most of them gawked in astonishment when they realized that my computers were still going and I was still working while their machines were all dead and their work day trashed!

Of course I wasn’t doing anything magical. I was simply using a device called an Uninterruptible Power Supply (UPS) or battery backup on all my computers and key network and communications hardware. If you’ve never heard of a UPS here’s what you need to know: The UPS plugs into the wall outlet and the computer and other key devices are in turn plugged into the UPS. If there is a problem with the voltage coming from the wall outlet the UPS can immediately switch to battery and continue providing safe levels of power to keep your hardware running just as if the outage or over voltage never occurred. Depending on the size of the battery and how much power the devices connected to it consume, the UPS will keep your machines running for several minutes to several hours. At a minimum, the UPS will give you enough time to save your work and safely shutdown your machines. Please note that a UPS is not the same thing as a cheaper and less effective surge protector. The surge protector will only protect your devices from over voltage or transient spikes. It cannot actually provide power when the line voltage is low or disconnected altogether. A UPS on the other hand almost always has surge and transient protection while offering the added ability to see your machines through a low power or outage condition.

I’ll confess that I learned the UPS lesson the hard way after losing data and scrambling an operating system disk many years ago. After that fiasco, I promised myself that from that day forward all my computers would be connected to a UPS. Keeping that promise has surely saved me more than I can possibly know. I have not suffered a loss of data due to power line disturbances since early 1995.

So, if you’re reading this post on a computer that’s not on a UPS, please know that death can come to your data and hard drive at any moment! It might be caused by a powerful lightning stroke from a distant thunderstorm, a glitch in the substation across town, the transformer down the street could suddenly explode, your daughter’s hair dryer could trip the home circuit breaker, or some nut that’s texting while driving could take down a utility pole that in turn causes a city-wide blackout. Regardless of the cause, you’ll find yourself suddenly in the dark and the document you’ve not saved in the last hour is gone forever. Worse, you may also find that key system files on your hard drive are now scrambled and/or the hardware is damaged to the point where your machine may not start again without a lot of work, if it in fact ever starts again!

There are many different types of UPS on the market. Prices run the gamut depending on how much stuff you need to power and for how long and whether you need automated and unattended shut down functions. For a typical home or office desktop machine with a large LCD monitor and a few peripherals I use a UPS rated at roughly 700 to 1000 VA. I look to have battery life of roughly 10 minutes at full load. More battery life can be helpful but isn’t necessary unless you’ve got programs or processes that must have maximum availability or cannot be shut down easily. I use a 1500 VA unit on my 8-core RAID server. This unit has an extra optional battery so it can keep going through longer outages. All of the backup units I use with my computers are called Smart-UPS and have the capability to send a signal (via USB or RS-232) to the computer when an outage is detected. This allows the computer to monitor the battery level and automatically and safely shut down before the battery runs out. The software to support automated shut down is built into most operating systems, but some UPS models come with enhanced software designed to handle this task. I recommend that you configure your computer to hibernate rather than actually shut down. If you shut down its possible to lose work that has not been saved. If you hibernate all of your work should be available again after you restart the machine just as it was when you left off.

I’ve had great success with APC Smart UPS over the years and I can highly recommend them. I’ve also recently started using a TrippLite model that looks quite nice as well. To save some cash you may consider a non-smart UPS to provide backup for your phones and other essential communications gear. I use a VOIP phone system through the home and office and I use these cheaper units to power the wireless Internet radio, the router, switch, digital PBX and phones. Since these things draw relatively little current even a small battery backup can power them for many hours.

Like many of the basic security solutions we discuss here it’s not so much about picking the best make or model that is important, but rather that you simply pick something and use it!


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