Compilation and configuration records.
I have been a little lax on documenting progress on the server largely because this journal is hosted on the very machine I am working on. Solaris 11 has a disadvantage compared to other Unixes because of lower availability of precompiled packages; and the ones that are available are usually outdated due to various reasons, but exacerbated by the smaller user base.
This leads to a lot of hand coding of setups and compiling of code over and above the typical linux distribution. It's laborious for sure, but gives the administrator ultimate control of how things work (or don't for that matter). There are highs and lows as one achieves incremental goals.
The problem is that once the work is done, unless you have stuck to standard install locations etc, rediscovering what you have done and how things tie in together can be another challenge. So documentation is key, or sticking to standards is a good practice.
I've found one thing that helps more than any other recently. When compiling code I keep the source code in a "src" directory in my home; and in the various build directories I create a file "BUILD-CONF" in which I place any of the compilation and configuration options I used.
This way, if I find that my compiled binary requires new features later and requires re-compiling I can use the previous options and add whatever I need to the former setup. Of course I update the compilation options file immediately before starting the 'make' command after a successful configuration.