What's your worst mistake / best lesson learned administering a server?

“Fail fast, learn fast” has become a bit of a mantra for entrepreneurs these days. While they’re not always as forgiving when their website is down, those of us on the technical side learn from our mistakes too.

We’ve all fat fingered a command or two, but what have you learned from it? Share your stories, not just of your worst sysadmin mistakes, but also of the best lessons you’ve learned from them.

Show comments

Submit an answer

This textbox defaults to using Markdown to format your answer.

You can type !ref in this text area to quickly search our full set of tutorials, documentation & marketplace offerings and insert the link!

Sign In or Sign Up to Answer

These answers are provided by our Community. If you find them useful, show some love by clicking the heart. If you run into issues leave a comment, or add your own answer to help others.

Want to learn more? Join the DigitalOcean Community!

Join our DigitalOcean community of over a million developers for free! Get help and share knowledge in Q&A, subscribe to topics of interest, and get courses and tools that will help you grow as a developer and scale your project or business.

Accidentally dropped a production database instead of a development one. Site naturally came crashing down.

Since then I double/triple check which server I’m connecting to before doing anything destructive.

I was rolling my own self-scaling cloud earlier this year via a nodejs script that spun up X number of droplets using the Digital Ocean API. In synchronous code, it would have been a simple for loop, but this was async and parallel. But I had set X to a fairly modest number (5) so I didn’t think much could go awry. First test, it becomes clear I wasn’t incrementing my loop correctly, and in the two seconds it took me to realize my mistake and hit Ctrl+C, I’d already created over 200 droplets on Digital Ocean! Luckily, I’d already created a script to mass delete droplets, so I was able to correct my mistake within a few minutes. Since then I have always implemented “dry run” versions of any script to test the control flow logic before I implement the actual commands.

Typing rm -rf /* instead of rm -rf ./*… Taught me to be far more carful when using sudo and globs.