Definition of JBOD in Network Encyclopedia.
What is JBOD?
JBOD Stands for “just a bunch of disks” and refers to any unstructured high-capacity disk-storage system. JBODs do not have the fault tolerance features of RAID disk systems. They are used for simple applications that require a large disk capacity.
A JBOD has no specified format – anything will do, including a collection of daisy-chained external Small Computer System Interface (SCSI) disk drives, removable Jaz drives, optical drives, or a mixture of different types of disk drives.
JBODs are difficult to manage and usually arise as a result of poor network planning as a company expands and upgrades its services. If you have a JBOD on your network, it is a good idea to migrate as much of your data as possible to a RAID-5 disk system, either an external hardware RAID-5 unit or a Microsoft Windows Server with RAID-5 implemented in software.
Because JBOD does not provide fault tolerance or performance enhancements, this 2001-era writer concludes, “JBOD doesn’t really have a lot to recommend it” over RAID 0 (a configuration that also lacks fault tolerance but at least offers performance improvements over individual hard drives or JBOD).
The only advantages JBOD offers over RAID 0 (or any other RAID configuration) are:
- Avoiding Drive Waste: If you have a number of odd-sized drives, JBOD will let you combine them into a single unit without loss of any capacity; a 10 GB drive and 30 GB would combine to make a 40 GB JBOD volume but only a 20 GB RAID 0 array. This may be an issue for those expanding an existing system, though with drives so cheap these days it’s a relatively small advantage.
- Easier Disaster Recovery: If a disk in a RAID 0 volume dies, the data on every disk in the array is essentially destroyed because all the files are striped; if a drive in a JBOD set dies then it may be easier to recover the files on the other drives (but then again, it might not, depending on how the operating system manages the disks.) Considering that you should be doing regular backups regardless and that even under JBOD recovery can be difficult, this too is a minor advantage.