View Full Version : Defraggin a RAID0 array

The Rock
8th June 2001, 12:39
Stupid question time: can you defrag a RAID0 array just as if it were a normal HD? This is my first RAID array, and it hasn't been defragged yet, and I dont want to lose 50GB worth of stuff.


8th June 2001, 12:43
Sointenly! But I like to back up the data before defragging because I just don't trust those things ... especially if you happened to lose power or such during the process. http://forums.murc.ws/ubb/frown.gif

8th June 2001, 12:50
It works fine and it is fast!

8th June 2001, 12:56
Xortam, that's what UPS's are for.

8th June 2001, 13:00
Is that pronounced Oops!? Yeah, I should get me one some day, especially living here in the dim Valley. I bought them for the servers at the office but never bothered with other than surge protectors at home. Haven't had a problem yet. Boy!!! I had really better go out and buy one now. http://forums.murc.ws/ubb/biggrin.gif BTW, I wanted to ask you about something ... I'll be back with a link concerning this side topic in a bit ...

8th June 2001, 13:10
Here it is ... "Voltage-reduction project may stave off blackouts" (http://www0.mercurycenter.com/local/center/volts0608.htm). I read this last night and was wondering if an UPS would boost the voltage level for me. As I recall, UPS simply switched over to batteries when there is a loss of power and surge protectors protected you from spikes and line conditioners took care of small variances. I know that some UPSs ship with all three elements. What do you recommend? I seem to recall that an UPS should handle brownouts.

Note: I don't know how long the linked article will remain available.

8th June 2001, 14:04
Come on, The Rock, there are no stupid questions.

I was guilty once too of having much invested in a PC and having only a power strip. Have had an APC UPS for a couple of years now. Got one big enough to run my PC and monitpr for 17 minutes, plenty of time to save what your doing if your there at the time, or it will shut down automatically after a power failure if your not.

Can hear the thing kick in and out every now and then. Or you can check the log if you like to see whats been going on.

8th June 2001, 14:51
A real UPS runs off of batteries all the time therefore there isn't any switching (cept the DC to AC coverter). Most UPS's today are SPS's (Standby Power Supply) which switch to batteries when a power failure is detected.

8th June 2001, 15:00
So is an APC UPS going to help me out with the reduced line voltages?

8th June 2001, 15:50
Maybe I should ask this in a new thread.

The Rock
8th June 2001, 16:52
Damn, now I need a UPS!! I swear you guys are part of some evil conspiracy to make me spend more on my machine; damn you all. http://forums.murc.ws/ubb/smile.gif Considering I've "upgraded" my machine to the tune of about $2000 in the last year, I probably SHOULD own one though.


8th June 2001, 17:00
"UPS on battery: Large Momentary Spike 130.0"
"Normal Power restored: UPS On Line."

Goes to battery for brownouts too.

So I don't got a real UPS?

8th June 2001, 17:25
No you have a Quasi UPS, a Semi UPS, The Diet Coke of UPS - Just one Battery... not UPS enough... LOL

My fiancee picked me up a Talking DR. EVIL doll at a garage sale... it only says one thing though.

"Very Well, Where Do I Begin, My Childhood was Typical, Summers in Rangoon - (It says something here like Loogeless), In the Summer We'd Make Meat Helmets."

Heh Heh.. http://forums.murc.ws/ubb/smile.gif

8th June 2001, 18:39
That would be "luge lessons".

8th June 2001, 18:49
Gadzooks... I think you are right... I can kinda hear it now http://forums.murc.ws/ubb/biggrin.gif

8th June 2001, 19:54
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...

8th June 2001, 20:08
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.

8th June 2001, 20:44
<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." http://forums.murc.ws/ubb/biggrin.gif

8th June 2001, 21:34
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. http://forums.murc.ws/ubb/smile.gif

8th June 2001, 22:26
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.

9th June 2001, 08:51
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.

9th June 2001, 09:09
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.