JBOD

In computing, a redundant array of independent disks (more commonly known as a RAID) is a system of using multiple hard drives for sharing or replicating data among the drives. Depending on the version chosen the benefit of RAID is a one or more of increased data integrity, fault-tolerance, performance or capacity compared to single drives. JBOD ("just a bunch of disks," or "just a bunch of drives") is a derogatory term - the official term is "spanning" - used to refer to a computer's hard disks plugged into a controller card that haven't been configured according to the RAID (for "redundant array of independent disks") system to increase fault tolerance and improve data access performance. Most disk controllers don't have any RAID functionality built into them. In these cases, the Operating System sees the disk drives connected to the controller as Just a Bunch Of hard Drives. In addition, many RAID controllers default to a JBOD configuration before being configured for RAID.