Notes from the hardware file
I keep a plain-text file of things I've learned about hardware in the last ten years. Most entries are one line. Some of them are below, lightly expanded.
- Consumer switches lie about their fans. "Silent" means "silent in a data centre".
- A UPS with a dead battery is worse than no UPS. It passes power through until the day it doesn't, and by then you've forgotten it's there. Replace the battery on a calendar, not on a beep.
- Label the cable at both ends. The end you can see is never the end you need.
- Thermal paste has a shelf life. The tube from 2018 is a tube of chalk.
- Buy two of the cheap thing. A spare USB-to-serial adapter or an extra SATA cable has saved more weekends than any expensive tool.
- Write down the BIOS settings. A reset-to-defaults after a battery dies will undo the boot order, the fan curve and the one setting you spent an evening finding.
- Rack rails are worth it. Every time.
The file is now about two hundred lines long and most of it is obvious in hindsight. That's fine; hindsight is what it's for.