Saturday, March 9, 2013

Dell PowerEdge 2950: Silence the Noise, Part 1



Background

Recently, I've accepted the task to build out a lab using donated equipment so people can practice for cyber security competitions.  This donated equipment includes four or five Dell PowerEdge servers; one 2950 and three or four 2850s.  After researching the system specs, the 2950 seemed like a good place to start since it was the model that could take the most additional memory.  It came with four 512 MB DIMMs (a whole gig!), but we swapped those out with  six 4GB DIMMs and an additional two 2GB DIMMs, enabling us to get to 28GB for memory.

Quick side note for others - the memory slots are paired 1-2, 3-4, 5-6, 7-8 so you can't have an odd man out.  I actually had five 4GB DIMMs, but I installed the fifth in slot 5 with a 2 GB stick in slot 6, and the start up checks kindly informed me of the mismatch.  Once I swapped out the 4GB so slots five through eight were homogeneous, I was good for memory and received no memory check errors.

The Issue

When powering on the 2950, it's idle fan sound is overbearing.  I live in a town home, and this server is placed in a closet in the basement 14 feet below the main floor yet I can still hear it whining away.  To say this server is loud isn't enough, it's LOUD.  

My first attempt at reducing the noise was to remove two of the four chassis fans, since this server isn't going to be heavily tested.  I put the cover on, powered it up, and went to the main floor to see the difference.  It was definitely an improvement, but I could still clearly hear the humming.    An audio meter indicates it's at about 70+ decibels, with two fans removed!

At this point, I figured I needed to take a look at these fans to see if there was a way to control their speed and/or look for acceptable replacements.  Research typically reveals one of three things:

  1. Brent Ozar's fine post about quieting a PowerEdge 1950
  2. Another author's post on hacking the BMI
  3. Multiple forums of people telling 2950 owners to buy a new box
Brent's post provides great advice on switching out the fans for a 1950, but the fans mentioned in his post are a different size than the 60mm x 60mm x 35mm of the 2950 fans.

Hacking the BMI seemed a little intimidating to start off with, so I decided to pursue that as the last option.

This equipment was donated expressly because of the lack of funds, so option 3 is out.

I decided to research alternate fans first...