As for hardware, there are 60 bay rackmount chassis out there that you can outfit with 60 20TB drives, which would give you just over 1.2PB. You would need a motherboard with enough PCIe lanes to use the needed number of HBA cards. If you went with HBA cards that can support 16 drives, you'd need 4 for 60 drives. I personally use the Pro WS WRX80E-SAGE SE WIFI, which might be overkill for your scenario, but the 7 16x lanes allows me 4x HBA cards + 1 GPU for Plex hardware transcoding/Steam streaming + 2 Hyper M.2 expansion cards for cache.
As for hardware, there are 60 bay rackmount chassis out there that you can outfit with 60 20TB drives, which would give you just over 1.2PB. You would need a motherboard with enough PCIe lanes to use the needed number of HBA cards. If you went with HBA cards that can support 16 drives, you'd need 4 for 60 drives. I personally use the Pro WS WRX80E-SAGE SE WIFI, which might be overkill for your scenario, but the 7 16x lanes allows me 4x HBA cards + 1 GPU for Plex hardware transcoding/Steam streaming + 2 Hyper M.2 expansion cards for cache.