The Dell PowerVault 220S enclosure is a 3U chassis that certainly weighs a ton when populated. It includes 14 3.5in hard disk drive bays that are easily removed for replacement, and a redundant power supply too. This unit is designed on the same basis as the Adaptec DuraStor 412R Storage enclosure, namely a JBOD. It contains no real smarts itself, so to gain optimum performance and/or redundancy, it really needs to be used in conjunction with a server that contains a SCSI RAID controller. Dell suggests using its PERC (Poweredge Expandable RAID controllers) in its Poweredge range of servers (how surprising)