Defraggin a RAID0 array

[MultimediaMan]

At the company I work for, we use a LARGE number of UPS devices (I think we're the single largest user of UPS devices in the world)...mostly ONEACs and Sola backup batteries, but there are a number of sites that use 8kV/A-H Liebert and Toshiba UPS units.

Most UPS units, to be truly effective, need REGULAR maintenance and battery cycling done to make them truly worthwhile.

Your Power Supply will be the single largest variable when it comes to voltage sags and spikes. Brownout conditions will cause the UPS to trip back and forth, and there WILL be voltage fluctuation when this occurs, whether or not it affects you is another matter. As an example, a well-known, respected (and unnamed) supplier for the company I work for uses a type of power supply in their servers that will drop to standby if voltage spikes or sags 5 volts from nominal...we get an abnormally high amount of calls and network warnings on these units during bad weather and days where utilities are straining, and ALL are on UPS units.

Better quality power supplies are beefy enough, and have enough capacitance to handle a fairly wide range of power conditions, but the aformentioned servers must use the low of the low...

[xortam]

Have you all read the link I provided?

<font face="Verdana, Arial, Helvetica" size="2">... Under the plan, California's major utilities would reduce the voltage delivered to homes and businesses from the present level of 120 volts, to perhaps 118 volts or 116 volts. ... ``You should aim not to go below 114 volts, with 110 as rock bottom,'' ...</font>

I'm concerned what that will do to my PC equipment. We're going to be at the utility's mercy to not bring voltages down to a dangerous level and not for too long a period. Can anybody recommend an affordable UPS (I always liked APC) that will be able to handle this abuse? MMM, will the systems you mentioned cope well with this scenario and what's the least expensive system I can get away with? I believe I have a good quality 300w power supply but I don't want to place an excessive strain on it.

[KvHagedorn]

<font face="Verdana, Arial, Helvetica" size="2">Is that pronounced Oops!?</font>

The only time UPS is pronouced "oops" is when it refers to United Parcel Service, as in: "Oops, I just dropped your new 21" monitor on the sidewalk."

[Greebe]

xortam, you needn't worry about dropping to 110vac. Most power on the lines will normally fluctuate by as much as +/- 10VAC (110-130vac). Above or below that, yes there is reason for concern. This fluctuation is designed into the supplies and are able to handle it without problems.

[xortam]

I understand there always is some fluctuation thus the need for line conditioners in some applications. I didn't recall how much the fluctuations are (you state +- 10 VAC) but I'm more concerned about the ability to handle sustained lower voltages versus brief fluctuations. The following paragraph caused me some alarm:

<font face="Verdana, Arial, Helvetica" size="2">Home appliances, computers and other equipment are normally rated to run best at about 115 volts. If voltage is dropped too low, say below 110 volts, it can damage appliances by overheating motors.

``If you permanently lower the voltage, you are subjecting your motors and compressors and appliances to greater stress and strain,'' said Ken Giles, a press officer for the U.S. Consumer Products Safety Commission. ``That will raise temperatures and can burn out motors.''</font>

I imagine PG&E will have to be very careful about how they manage this voltage reduction as to not harm equipment or they would be facing one hellacious class action law suit with big business leading the charge. Still, I would think that this may cause problems for those PC users who are o/c'ing their systems and have marginal power supplies.

[MultimediaMan]

It would bother me, too. I seem to recall some Soviet-Era "plan" that sought to do what the Utilities in California are attempting, The result was major damage to almost all of the electric motors in the entire Volgograd Industrial Basin...this was about 20 years ago, I think.

It didn't work then, I don't think it will work now.

[xortam]

So I keep coming back to asking opinions on what would be the best way to go about assuring that I won't incur any damage (specific equipment recommendations). I'd appreciate suggestions from anybody knowledgeable about UPS/SPS systems that will protect against this scenario. I should probably buy an SPS anyway so I may as well get one that will protect me from this possible stressing voltage situation. Maybe I'm just fortunate, but I've never had a problem due to power loss in 18 years of PC use. I recall one memorable incident in '83 when I was writing to disk on an IBM PC XT when a power line transformer blew and took out the entire area. I was amazed that there was no data corruption or equipment failure once the power was restored. I was very impressed ... and perhaps lucky.