The case holds 5, the bays that I'm also mounting hold 4 each for both of my RAID partitions. So it'll be 13 drives total if I don't find a way to add more 🤣
I don't even know how my TB I have at this point. I use RAID 10 so storage is cut in half, but I use 8TB drives, so it's still a ton. Then I have a main boot SSD, with a live backup SSD, then a third SSD that I swap to mirror every couple of months and then stash away. That will probably be done in an external bay that I have for swapping though.
Plan to have somewhere between 40-60 TB when it's in full operation, but I don't know if I have ever reached a point where I considered a computer project "complete"... it's usually more of a never-ending process than a specific task with an end goal, lol.