4 Things to Know About the TerraMaster F4-421
No PCIe expansion slot The F4-421 lacks a PCIe slot, so you cannot add a 10GbE card or other internal upgrades.
No external expansion support You cannot connect external expansion units to add more drive bays.
Limited to four internal bays You are stuck with the four internal drive bays, so plan your storage capacity and RAID layout carefully before filling them.
Plan ahead for storage needs Because you cannot expand later, decide on your total storage requirements upfront and choose drive sizes accordingly.