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I have a raid 1 that has failed partially. The controller tells me the raid is degraded, but does not tell me which drive is failing.

When I look in My Computer, I see that the controller split my raid 1 two the separate drives, so now I have two of the same partitions. I can read data from both them just fine. The SMART status is being dumb and says no errors.

One drive is making a clicking sound, but I can't tell which one. Can I amplify the sound some how to locate it?

What are some tricks/tips I can do to figure out which drive is failing without taking the computer down and swapping drives? I am trying to minimize down time.

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You'll also want to be sure you have good backups, in case you pick the wrong one. – Michael Kohne May 28 '09 at 19:52
What sort of controller is it? Even my cheap Adaptecs will tell me drive statuses if I pop into the controller setup while booting. – Chris_K May 28 '09 at 20:50
up vote 11 down vote accepted

Poor man's stethoscope: Long'ish screwdriver. Tip on the drive, handle on your ear. Listen to each drive. If either clicks you should be able to quickly isolate it.

(Works great with valve-covers on your old cars when listening for valve noise too ;-) )

Of course, this assumes clearance and common sense about where on the drive you touch...

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In the time it took me to write my answer you posted a very similar one good thinking this has actually worked for me. +1 great minds think alike! – Copas May 28 '09 at 18:03

An old back-woods mechanic trick can come in handy for this kind of thing. I once saw an old mechanic old a long straight stick hard against the palm of his hand and then press his knuckle up against his ear. He placed the other end of the stick on parts of the engine and could hear which cylinder was not firing correctly. Wood conducts sound well if it has no gap air gap to jump. If your old enough you might remember in movies a cowboy putting his ear to the train track to tell if a train is coming or the Indian listening to the ground to hear the buffalo. The same principle applies here. As crazy as this sounds you can use it to track down the clicking sound, give it a try.

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+1 - great minds indeed :) – Chris_K May 28 '09 at 20:49

Looking in the event log, you should have an event from the disk source:

Log: System
Source: disk
Event ID: 7
Message: The device, \Device\Harddisk4\DR3, has a bad block.

alt text

And then to identify DR3, you find Disk 3 in Disk Management:

enter image description here

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How do you relate \Device\Harddisk4\DR4 to a particular physical disk? – Roger Lipscombe Nov 22 '11 at 14:15
@RogerLipscombe Updated with screenshot. tl;dl: Find Disk 4* to find **DR4 – Ian Boyd Nov 22 '11 at 14:33

HDTune is a great tool. You can run an error scan and find the over all health of your disks. Go to and download the free version.

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If you can get at the drives, and the clicking sound is quite regular you can place your hand on top of the drive and often feel when the click occurs in one drive or the other.

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If you can physically touch the drives, you should be able to determine which one is clicking, since the click is (I believe?) caused by the motor moving the head to the end of the platter repeatedly.

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Disk Management (diskmgmt.msc) may give an indication.

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