I have a Dell PowerEdge 1950 rackmount server. It hosts an important SQL database, and in the past month or so, it has become very loud, which is irritating and distracting me.
I ran some basic tests through Windows to check resource utilization (CPU usage, disk /IO, etc.), but didn't see anything that stood out.
In order to get the noise down to a tolerable level, I'd like to know what might be causing this. What factors affect the noise level of a server?
The main noise will be coming from the fans - servers have many different ones on the CPUs, Memory, Disks, Case etc. In some cases these will dynamically adjust their speeds based on the temperature they detect but in many they just run at what ever speed they are set to either manually or in the BIOS.
I'm not sure whether the 1950 has the ability to automatically adjust their speed. If they are, it will generally be a setting in the BIOS.
1U servers are always noisy. If it sounds like a small jet engine in there, that's because it kind of is. The fans in a 1U server are so small that they need to spin at ~10,000 RPM to move enough air to cool the server when it's under full load.
The fan speed is generally variable, so at boot time and other times of heavy load, they spin up to their maximum RPMs, which is quite loud, but they'll spin down to a slower, quiet speed once the server's need for thermal dissipation decreases. You can monitor the fan speed with (among other things) the Dell OpenManage software.
I would personally use that (or whatever hardware monitoring system you use) to check on the temperatures inside the server, as well as make sure the probes and sensors for the fans are operating properly and within normal voltage ranges.
But, to some extent, this is normal, especially given the age of the 1950 PowerEdge platform. If the noise is really a concern, try cleaning and oiling the fans, or replacing the old ones in there with new ones. Airflow restrictions could also be causing sub-optimal cooling and requiring higher fan speeds, as could an increase in ambient temperatures, or increased air temp near the fan intakes. General age and contaminant build-up can also be an issue, so it might be worthwhile to pull out the server, take a can of compressed air to blow out any dust and grime, which can negatively impact cooling and heat-dissipation within the server as well.
If none of that helps, and you have reason to be concerned, you might want to consider the possibility that the server's starting to give up the ghost - hardware's running hot, out of normal voltage ranges, and is showing the first signs of an impending hardware failure.