JBOD (which stands for “just a bunch of disks”) generally refers to a collection of hard disks that have not been configured to act as a redundant array of independent disks (RAID) array.
JBOD is an alternative to using a RAID configuration. Rather than configuring a storage array to use a RAID level, the disks within the array are either spanned or treated as independent disks. Spanning configurations use a technique called concatenation to combine the capacity of all of the disks into a single, large logical disk. Although some RAID levels also concatenate disks, numbered RAID levels generally use striping or parity while JBOD does not.