you buy a NAS, load it with drives (8, 12 or 16), create a static volume, and make it RAID 6. (some newer systems allow for RAID 60). I would never do RAID 1+0. To create an expandable volume, you need to make a "thick volume" which is a storage pool. Again, I never do this. I need performance to be able to do 4K, 6K and 8K editing for multiple users. And I need to plan for failure, so if I add another chassis, I don't care it expands to the same "MediaRAID" - it's ok if it's another volume that mounts. As long as if I have a power supply failure on a chassis, my entire system does not go down. Reliability is much more important than convenience.