How to Make a Dell PowerEdge Quieter

I’ve got a few servers in my home lab and I’ve always taken steps to make sure they’re quiet.  I like running my lab out of my office closet, but I don’t want to hear any of them running.  I’ve blogged about how to build a silent PC, but today I’m tackling another noisy beast – an off-the-rack server.

Dell PowerEdge 1900 Internals

Quest got me a Dell PowerEdge 1900 to use as a virtualization host, and it’s been great.  Two quad-core CPUs, 16gb of memory, six SATA drives in a RAID 10, and about a hundred pounds of solid steel.  Seriously, the case is bulletproof and gawdawful heavy.

But it’s loud.  Deafeningly loud.  It’s got 6 92mm fans that can wake the dead.  They’re temperature-controlled, so they don’t go full blast unless the server’s working hard, but even at very light loads they’re just way too loud.  I couldn’t carry on a conversation next to this server, let alone record a podcast.  This wasn’t a problem when I had the server in the basement, but now that I’ve moved to Chicago and my “datacenter” is my home office closet, it’s a problem.  I can’t run cables inside the walls since it’s a rented condo, and I can’t run cables along the floor because I’ve got a girlfriend with a keen sense of design.

The Fix: Replacing the PowerEdge Fans

The stock fans are Nidec BetaV TA350DC 92mm fans that:

• Move up to 150 cubic feet of air per minute
• Spin at up to 6,000 RPM
• Scream at 57 decibels – not quite as loud as yo momma, but close
• Have pulse width modulation (PWM) speed control – the motherboard can control the fan speed based on how hot the server gets

Removing a Fan

Fans like this rely on very fast rotation speeds to push a lot of air, but the faster the blade spins, the more noise it makes.  Quiet-PC freaks like me turn to fans that turn slower, yet still push a lot of air.  I bought six Nexus PWM Series DF1209SL-3PWM fans from Newegg for $10 each that:

• Move up to 43 CFM
• Spin up to 2,500 RPM
• Whisper at 16 decibels
• Also allow PWM speed control

If you don’t get fans that are PWM-controlled, then the Dell motherboard will freak out upon boot-up and think there’s no fans connected.  Some models will wait for the user to hit a key to acknowledge that error, and I don’t want that happening – I leave my servers in the closet without a monitor attached.

PowerEdge Fan Cage

The Good News: It’s Easy to Swap the Fans

Unlike some vendors, Dell’s fans use a removable cage surrounding an industry-standard fan.  Just pop the fans out of their orange cases – no tools required – and pop in the new one.

Any 92mm fan up to 38mm thick will work, and thinner fans like the Nexus work fine too.  One side of the fan cage has click-on tabs that hold the fan in, so even thin ones are fine.

The power cable is even easy to remove, but about that power cable…

The Bad News: The Power Cables are Proprietary

Unfortunately, even with PWM-controlled fans like the Nexus, the pin connections don’t match Dell’s proprietary connector.

Fan power cables aren’t plug-and-play either.  You’ll need to bust out the solder gun to cut the Dell fan cable leads and attach them to the Nexus fan’s power cables.  Both the Nexus and the Nidec fans have the same number of wires, and the same color codes.  Connecting them is just a matter of cutting the cables away from the power connectors and soldering them together.

Just Like Disarming That Bomb

The Result: Enjoying the Silence

I can’t believe what a difference it made.  I can hear again.  I can record podcasts with the server running in the closet right behind me.

I haven’t taken scientific measurements, but the PowerEdge now sounds roughly similar to a home-built desktop.  It’s not as quiet as my home-built silent PC or my Optiplex 360, but it’s more than quiet enough to work with in the closet.

The PWM fan controls work smoothly too, reporting back their speed to the motherboard just like the native fans.  Below is a screenshot of VMware Virtual Center showing the fan speeds, happily spinning along well below their maximum speeds.  I’ve seen them running faster (2250 RPM) during heavy load, which tells me that the motherboard is throttling down the fans.  That would seem to indicate that the motherboard isn’t overheating, because the motherboard doesn’t feel the need to ramp up fan speeds to full blast.  That’s what I call a success.

vSphere Fan Alert

The Drawbacks

One problem shown above is that sometimes fans spin slow enough that they trigger Dell’s thresholds for slow-moving fans.  This isn’t a problem by itself, but since vSphere color-codes servers according to their alerts, this means that my host goes red a lot, but I have to switch over to the alert screen to find out if it’s just a slow fan or something more serious.  Gotta figure out how to fix that for good one of these days.

Because the fans are so quiet when they’re running slow, I’m also much more aware of the server’s load now.  When I start doing CPU-intensive stuff, I hear the fans start to spin up louder – something I wouldn’t have noticed before when the fans were always running full steam.  Even at their loudest, they’re still quieter than the stock fans, but the changing fan speeds can break my concentration sometimes.  (I’m easily distracted.)

Another problem is that the server isn’t any cooler.  This server lives in my office closet, but I can’t close that door or else it gets hotter and hotter in there.  I leave my office window open full time, even in the Chicago winter.

Next time we move, though, I’ll try to get a condo with a bathroom adjacent to my home office.  I’ve got this dream of using the toilet tank water and a liquid-to-liquid cooling exchange to get silent cooling.  But that’s another blog post…

Note: I’m on a cruise ship this week and won’t be responding to comments until Monday, January 11th.  If you post a comment that requires moderation, don’t fret – I’ll approve it when I get back.

Brent Ozar

Brent specializes in performance tuning for SQL Server, VMware, and storage. He's one of the very few Microsoft Certified Masters of SQL Server, a published author, and a Microsoft MVP. He likes travel, Jeeps, Apple gear, jokes, and writing about himself in the third person. Read more and contact Brent.

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