I've recently bought an R720xd and set it up with Win2012/Hyper-V. Well, the server was running without any issues for two weeks until a disk a failure. I have already requested for a replacement of the drives and the server was on RAID as seen below;

  • OS - RAID 1 (mirrored)
  • DATA - RAID 10 (striped and mirrored)

Later yesterday there was a power cut and I had to shutdown the server. I can confirm it was a smooth power off. However, I have switched on the server once the power was back where the server started smoothly with a huge fan noise, then went back to OS boot and then while on login screen, it fired up the fans with a huge noise. Checked the Dell's OMSA for any log reports but all showed normal, even the fans.

Then I restarted just to make sure that I didn't miss anything and it powered on smoothly but again back to the old noise upon showing the Windows login screen. However, this time it was average noise. So, I left it up and came back morning to see where it was the same but the noise has increased a little.

What I cannot figure out is, whether this is due to disk failure where it is trying to rebuild or sort of working on degrade mode or is it due to something else. Any advise will be appreciated.

  • Always after an interruption in power the fans will kick on real high at startup then go back to normal. They are also temperature controlled so could change with heat. In addition if you have the cover open the fans will kick on high. Commented Feb 14 at 4:36

3 Answers 3


Fan noise is usually attributed to either some object hitting the blade or the bearings. Neither of which will appear in any log nor detectable by software unless the RPM (fan speed) slows. You may have bought it brand new but parts like fans are made by the lowest bidder. Do your best to determine the source.. mobo fans, psu fan, etc. Contact support and get them to send a new unit.

  • I have checked through OMSA, and even used DSET to identify as well. I'm assuming that it could be due to the degraded RAID as the server is trying to figure out from the hardware level. Fans are actually at 9100 RPM average.
    – AzkerM
    Commented Apr 4, 2016 at 7:57
  • But have you narrowed it down to a specific fan or is it all over then (minus the PSU fan(s))
    – Skeer
    Commented Apr 4, 2016 at 13:16
  • It is precisely all of them...
    – AzkerM
    Commented Apr 4, 2016 at 13:49
  • Hmm.. and the array is in a degraded state or it is working correctly?
    – Skeer
    Commented Apr 4, 2016 at 14:13
  • Nope! As I have explained above, it is still on degrade mode waiting for a disk replacement.. I'm waiting for the disk to reach my location.. :)
    – AzkerM
    Commented Apr 4, 2016 at 14:27

Yes, if the array is rebuilding and you are using an high-end PERC card (ie: H710/20/30 etc), it can be related to that. Wait until the rebuild is complete. If the issue persists, use omsa or the integrated IPMI to be sure no other disk are reported as Critical and no other array show as Degraded.


The bearings in one or more fans may be bad. It's always a good idea to have a few spare fans on hand. The cover of this server can be removed for a maximum of 5 minutes while the system is powered on. Of course the system will know the cover is open and the fans will spin up to almost 100% of it's RPM's. The fans are hot-swappable and in a line behind the front HDD backplane, so my suggestion is to remove the fans, one at a time of course, to see which fan is making the noise. Order a replacement so when you find the culprit you can swap it out right there. Make sure you replace the cover before the end of the 5 minutes as you don't want the system to overheat.

  • The issue was already resolved in the comments of this old answer here: serverfault.com/a/767860/37681
    – HBruijn
    Commented Feb 13 at 12:07
  • @HBruijn But then, how do we solve this question when it has already been solved? We really need a function to promote an answer.
    – djdomi
    Commented Feb 14 at 9:18

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