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Re: RAID 5 Multiple Hard-drives failure

Bob Chiodini wrote:
On Tue, 2006-03-14 at 10:26 -0500, Reuben D. Budiardja wrote:
On Tuesday 14 March 2006 08:55, Bob Chiodini wrote:
On Tue, 2006-03-14 at 08:21 -0500, Reuben D. Budiardja wrote:

Have you checked the power supply?
I have not checked the power supply for the system. Any recommendation on how to do so ?
Have all of your failures been in the same machine?
Yes, all in the same machine, that's why I suspect there's something else physically wrong.

Thank you.
Reuben D. Budiardja
Dept. Physics and Astronomy
University of Tennessee, Knoxville, TN


Open up the case and find an unused drive power connector.  Measure the
voltage between the yellow and black, should be ~12VDC.  The voltage
between the red and black should be ~5VDC.  I'm not sure what the
tolerances are for your drives, maybe it's on their website.  As a rule
of thumb, I'd not let the 12V get below 11.9V or above 12.1V (about
10%). The 5V should be above 4.8V and below 5.1V.  These are guidelines.
The last time I opened a PC power supply the 12 and 5 volt supplies were
not independently adjustable.

Your BIOS may also tell you these voltages, along with various
temperatures.  lm_sensors might work as well.


One thing to try when testing the power supply as above is to make sure you 'load' the system.

When the system is idle (or close to idling), the 12V for example, might be 11.99V. But when you start spinning up multiple hard drives, this puts a load on the power supply.
If there is fault with the power supply, it will cause the voltages to drop.

'Most' PC PSU's are meant to be constant voltage type, ie. they try to maintain their voltage outputs as close to spec as possible (+5v,-5v,+12v,-12v, 3v etc etc etc). If you took most PC PSU's out of the case and measured their outputs with nothing connected, you would read near exact values.

It is only when you place them under load that the outputs will vary or indicate a fault.

So while measuring, try to run some sort of 'stress' test on select items of kit / various items of kit.

Also worth pointing out, is that a lot of people these days are inserting extra fans inside their machines, and these sometimes have thermostatic controllers on them to switch them on at a certain temp. Some fans are electrically noisy, and of course, that noise will also only be present when the fan is running. Likewise, they will only 'load' the system when they too are running.

So in summary, make sure you are running as much of a stress test as you can (without making it a destructive stress test).



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