Hey everyone, just started hoarding Movies/Shows on my Plex server and I'm looking to expand the right way.

Currently I have a single 4TB hhd and it's almost full so I want to expand with some redundancy. My current plan was to buy 3 more 4TB's and run them in RAID 5 until they're full then build another pool using bigger drives but I've never used RAID before so I have some questions.

My Plex server runs off a 13100 and Ubuntu. Do I need a hardware RAID card or will software be good enough? With RAID 5 can I add extra drives to the pool afterwards without loosing data? I was going to buy 3 more so I can set up the pool, transfer the data from the 4TB I already have then add it to the pool too, is that possible?

Seem to be getting a lot of mixed answers on Google so thanks in advance for the help!