I want to build a proper server with room for 40+ HDDs to move my media server to and have RAID 1. I know a lot about PCs and software, but when it comes to server hardware I have no clue what I’m doing. How would I go about building a server that has access to 40+ RAID 1’d HDDs?
You need to research raid 1,6,10 and zfs first. Make an informed decision and go from there. You’re basing the number of drives off of (uninformed) assumptions and that’s going to drive all of your decisions the wrong way. Start with figuring out your target storage amount and how many drive failures you can tolerate.