Rules of Thumb of System Administration - Steve Simmons and Elizabeth Zwicky Abstract: Every profession accumulates some condensed wisdom, whether it's in the form of Zen koans or laws of engineering. This presentation is a tour through the condensed wisdom of systems adminstration, in the form of pithy sayings supported by educational stories (some of them, of course, stolen from other professions, including Zen koans and laws of engineering.) Some of the talk was originally based on the following web page: Simmons' Laws of System Administration http://www.nnaf.net/~scs/TechWriting/laws.html These are only the rules that I was able to write down. Check out the URL above for more. --- Your job would be much easier without users. Your job wouldn't exist without users. --- Excellence increases demands. --- First impressions only count when it hurts. --- All other things being equal, everyone's favorite repair option is the most violent. --- When in doubt, shut it down, count to ten very slowly, and start it back up again. --- If you don't know why you did something, you have done the wrong thing. Corollary: If you don't document why you did it, someone else will do the wrong thing. --- People never ask for backups, but they do ask for restores. --- Every seasoned system administrator has at least two stories about backups; the punchline to one of them is "What Backups?" --- Estimating time Take the time that you think it will take, multiply by two, change units to the next order of magnitude. 1 hour => 2 days. If you think this is crazy, change your multiplier to four. --- There is no such thing as a one-time program or a temporary fix. --- "Secure" is to "computing" as "low-fat" is to "food". --- Free software isn't free. --- Free hardware is actually more expensive than hardware you buy. --- Advice is often valued by what you paid for it. --- The operating system is not your enemy. Even if it is evil. The applications are. Even when they aren't evil. Corollary: Once an application is too tightly integrated with the operating system, everything is against you. --- No matter how bad it is, it can get worse. Sometimes spectacularly so. --- Paranoia is a job requirement for system administrators. --- If it can be shipped in more than one box, it will be. --- No program is so obsolete that nobody wants it anymore. --- If you tell them that it will be faster, it won't be fast enough. If you tell them that it will be slower, it will always be slower, even if you are wrong. --- Pure logic is like a purple stretch velvet minidress: perfect in the right context, but not always appropriate. --- There is no such thing as enough disk space, CPU power, cable already run, or network bandwidth. --- Whether or not people have a right to avoid self-incrimination, they will exercise it. --- Just because you can doesn't mean that you should.