Drobo S Beyond Raid 5-Bay USB 3.0/FireWire 800/eSATA/SATA 6GB/S Storage Array with Drobo PC Backup DRDR4A21 BeyondRAID leverages RAID's protection methodologies, including mirroring and striping with parity The eSATA interface on Drobo S transfers data up to 50% faster than FireWire 800 Instantly expand your available capacity by hot swapping in an additional drive, or replacing an existing drive with a larger-capacity one Enable the dual-drive redundancy option to protect your data from failure of up to two hard drives With its self-healing technology, Drobo S keeps your data safer than ever