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All of a sudden, the power supply of a server started to smell real bad. One of the hot swappable power supply units died. We replaced it, booted up Windows Server 2003 to find out that 2 out of 4 drives in a RAID 5 configuration had died.

We're also getting MACHINE_CHECK_EXCEPTION BSOD's everyone once in a while.

How realistic is it that the power supply did this to the RAID? The RAID was confirmed to be working minutes before this happened (we were using the RAID right before we noticed the awful smell).

Thanks for any advice given! :)

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Why would you need to boot Windows again if the power supply was hot swappable? – womble Nov 12 '09 at 18:02
Only had one power cord at the time. – bobber205 Nov 12 '09 at 18:14
Not having that second power supply connected could have contributed to the RAID failure as well... If a system has two power supplies you really should have them both connected. – Zoredache Nov 13 '09 at 5:08

Although it shouldn't happen with a well designed power supply the reality is that this does happen all too often. As the unit is dying it may lose voltage regulation capability, resulting in over-voltage power being supplied to the machine. If you've good cooked drives as a result you need to be prepared for other components to fail as well. Ideally the server should be taken off line and stress tested but who has the tools to do that these days?

Assuming you have redundant power supplies, rather than just a single hot swap unit, you would be well advised to get hold of another power cable as well. After all, there's no point in having such gear if you're not going to be able to use it properly.

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This can happen, which is why it is advised to have redundant power supplies in a server and/or a RAID controller with a BBU installed.

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let's consider this situation for a moment. a malfunctioning source of power can do only 2 things at a moment of time, give more energy than needed or less. if it gives less when drives are writing to the disks heads can potentially drop on the surface and damage it and data, this really shouldn't happen with any modern hard drive, heads are parked in such case (…). but if for whatever reason more energy is supplied to a drive and its controller fries, how is having a second power supply will save you? – monomyth Nov 13 '09 at 8:23

While it's possible that a bad power supply could potentially damage components I think this is unlikely. If the two drives were the only two drives on a particular power line then I would suspect that the power supply may have sent more than 12v down that line. Otherwise it's probably more likely that you had a few bad drives in your array that you weren't aware of. Powering them down just manifested the problem. Anytime you stop a drive that's been spinning non-stop for years you run the risk that it may not restart properly.

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