Full original in:
- Never do something you can't undo.
- Always check the backups, never assume they are working. Make sure you can restore from them, too.
- Write down what you did, even if you know you will never forget it, you will.
- If you do it more than once, write a script.
- Get to know your users before there is a problem, then when there is, they will know who you are and maybe have a little understanding.
- Remember you are performing a service for your users, you don't own the system, you just get to play with it.
- Check your backups.
- Never stop learning, there is always something you should know to make your job easier and your system more stable and secure.
- Check your backups, again.