What are these notes for?
In my life I was working for many companies affiliated with unix projects. If the management of this company was good, there was time, when developers' team(mainly production engeneers) were stuck. The popularity of project was growing and servers weren't able to adequatly handle the load growth. Some of the firms were just buying faster servers, blades and so on. But if the project (and the firm) was young, it just haven't got enough investments to do so. And we were put the task how to work on servers we got.
5 years of hard work told me, that the extensive solution is often the wrong way. Optimising and tuning is a better and more interesting, than just spending money. Some of the tips and tricks i'll try to write here.