What guides, wikis, or megathreads are available for those new to archiving and storing data?

I've recently aquired the hardware to build a home server/NAS. I'd love to know some community-guided advice on tools I should consider, and what best practices are?

For instance, how does redundancy work? Whay about automated backups? What OS should be running on a NAS? What utilities can I use to monitor the safety of my data? Perhaps even a guide about how to safely share that data outside my home network for personal use, or even open for the internet, without compromising my network?

Thanks for the discussion