MB

I was looking for a small web server for service static files bundled in a container image. Most people just use nginx because it fast and well maintained. But the base image is 68.6 MB! Even going to the alpine-slim instead of latest only gets us down to 5.27 MB. You can also use BusyBox to serve HTTP or even better compile your own BusyBox and strip everythong down as show in this blog. That gets use down to 154 KB. This is already a huge improvement but we can go down to double digits using darkhttpd, 62.8 KB. Bundling one image in your static site would already negate all the improvements of not using nginx but it is still cool to see that we still can get things done with something that would fit on a floppy disk.

Docker vs Native binary

Tested the backend of this blog on small VM on my desktop with both a native binary and Docker to compare performance. My desktop could have a lot of variance so this test is not that accurate. The VM has 2GB of ram and 4 cores allocated. Memory is not limiting factor as the webserver uses 20MB at most. All 4 cores are utilised but the one core is always more used then the other, I assume that this is the case because the webserver is database limited for the most part. SQLite is in some ways single threaded.

  1  [|||||||||||||||||||||||||||||||   78.5%] 
  2  [||||||||||||||||||||||||||||||||  80.2%] 
  3  [||||||||||||||||||||||||||||||||  80.3%]
  4  [||||||||||||||||||||||||||||||||||95.7%]

I used the latest version at the time of writing.

I did 3 runs of each, alternating between the two version to limit variation. I used a tool called bombardier with 20 concurrent connections for every 10 second run. The requests are made from the host machine to give the webserver the whole VM to itself. This does add extra overhead but it is the same for both versions, so for sake of comparison this is fine.

These are the averaged results for both versions.

Binary

Statistics        Avg      Stdev        Max
  Reqs/sec       262.03     152.02     913.95
  Latency       75.22ms    53.44ms      0.93s
  Latency Distribution
     50%    71.05ms
     75%   104.18ms
     90%   127.14ms
     95%   143.13ms
     99%   188.12ms
  HTTP codes:
    1xx - 0, 2xx - 2643, 3xx - 0, 4xx - 0, 5xx - 0
    others - 0
  Throughput:     3.15MB/s

Docker

Statistics        Avg      Stdev        Max
  Reqs/sec       260.70     150.30     962.85
  Latency       76.59ms    53.97ms      0.95s
  Latency Distribution
     50%    70.67ms
     75%   107.55ms
     90%   135.69ms
     95%   151.88ms
     99%   197.22ms
  HTTP codes:
    1xx - 0, 2xx - 2622, 3xx - 0, 4xx - 0, 5xx - 0
    others - 0
  Throughput:     3.12MB/s

These results are really close with a very slight edge for the binary. Only 0.5% more requests per second and 1.78% lower latency on average. This is within the margin of error for this unstable setup. But even if we would take these results as 100% accurate I still think it is worth the small hit in performance. This small hit is probably even smaller when you are using a bigger server on more native hardware.