Performance Testing SlimNAS
It should be obvious that the little T5700 is not going to be as responsive as the P4-2.8 tower that it replaced. Interaction with the web GUI is not as snappy, but it’s good enough for my needs.
Since I have several Squeezeboxes I decided to do some simple throughput testing to ensure the 1 GHz CPU and one little 2.5″ disk would suffice when feeding various combinations of music streams from disk and internet sources. FreeNAS makes such testing very simple as it provides a dynamic graphic of both CPU usage and network traffic.
I started start by checking the baseline CPU usage when merely logged into the FreeNAS web interface and watching the CPU graph.
Before we can play any music we need to let the SqueezeCenter software scan the storage and build a database of the files it finds.
The highest CPU usage was displayed when the server was actively scanning the music library to build its database. This only needs to happen occasionally, after you’ve added some new content. The process of scanning my 40,000 songs took about 30 minutes (?) during which time the server was completely unresponsive, unable to play and even unable to offer its web GUI.
Once the database was built the server was much more rational. I proceeded with further CPU and throughput tests starting with listening to a song in flac format.
The CPU use shown during the idle period reflects the load presented by the FreeNAS web GUI including the graphing utility. The CPU load spiked during interaction with the Squeeze Center web GUI. The music stream only consumed about 10% of CPU power.
This time the heaviest CPU usage was shown when interacting with the web interface. The internet radio stream consumed about 5% of CPU, and the flac file about 10%. By this measure users with a single Squeezebox would find the little T5700 more than adequate.
Next, I measured CPU usage and network traffic while streaming music to two Squeezeboxes. Then finally, all three Squeezeboxes.
In all cases the music played without interruption and during playback the Squeeze Center web interface remained functional.
I also tried playing three separate streams, that is, a different song on each system, as well as all three systems in sync. This did not seem to make any difference to either CPU usage or network throughput.
This project has been just full of advantages. Since completing this project the old P4 server has been repurposed and I don’t miss it a bit. Being silent the T5700 now resides in the same room where I do most of my more critical listening, without making an audible impression.
Migrating from a tower PC to an appliance-like platform allowed me add it to my UPS without worrying about overloading the UPS. The system draws a very modest 14 watts. Drawing less power is great since it’s left running 24/7.
Lastly, I saved a nice little box from going to the landfill. Its useful life is extended as it will be serving up music around our house for the next few years.