Sunny Days 13 – Tweaking the Sun

Actually, this is going to be mostly a reference point for me but you might find the information here interesting as well. Over the last few weeks I had the chance to play with two machines from Sun: my T2000 and a X4100. Since the primary goal was to set them up as high speed web servers, I did some research on the net and found that there’s a lot of parameters you can – and should – fine tune.

The most compact listing can be found on Jens-S. Vöckler’s site. Although a bit dated the information there is quite accurate and I especially like the scripts provided there.

In addition, you should read the Solaris Tunable Parameters Reference Manual. It contains updated information and the description of some newly added tunable options.

Using all the hints and tweaking some parameters a bit more aggressively, I could squeeze a good amount of additional performance out of the Suns. However, I’m still stuck on the Galaxy because of a hardware bottleneck. As it seems, the hard drives used in the machine have a bug causing them to be really, really slooooooow when writing data. Thus they are the major cause for skyrocketing loads when there’s a lot of web traffic to be handled. In case your server experience unexpected load peaks, watch the hard drive activity closely, using something like “iostat -xn 1”. If one of the devices shows a busy percentage of 100 percent, you’d better call Sun and have them fix the problem.