What is JBOD and how does it work?
If you’re looking for an affordable, large capacity storage solution to get your data center off the ground, there are plenty of options out there, but none quite as accessible as JBOD. JBOD or “just a bunch of disks” storage offers unique benefits that aren’t available with other storage options and those benefits can save you time and hassle.
Lets assume you have some hard drives available already but they all vary in size. With a RAID configuration, you lose a large fraction of your available space as it is used for redundancy. For instance, a 20 GB HD and another 20 GB HD would combine to make only a 20 GB RAID 0 volume. With JBOD on the other hand, the same to drives would combine to make a 40 GB JBOD volume. With JBOD, absolutely no storage space is lost when combining volumes. One could think of JBOD as the opposite of partitioning where, instead of splitting up a disk, you are combining multiple disks.
So what makes JBOD so useful?
If you are expanding an existing system or have a variety of disks of varying sizes but want to combine them into single larger, more useful disk, JBOD can do just that without losing a single byte of capacity. Additionally, JBOD allows you to expand your storage space using disks placed outside of the server, which can come in handy when dealing with existing systems that are already at capacity. Even systems that are not at full capacity can be expanded with external disks to allow space for more processors.
In a typical RAID 0 setup, if one of the drives involved fails, it is difficult if not impossible to recover the data because the disks are striped. This means that the disks are dependent upon each other. In a JBOD setup however, the disks are essentially independent aside from being read as one single drive. So data that was not on the failed drive is relatively simple to recover.
If you are using a rackmount chassis set up, you can purchase a JBOD enclosure for enterprise class set-ups that often feature hot-swappable disk drives so you can insert your own 2.5″/3.5″ drives. The average JBOD enclosure usually features unique performance options like cooling fans and internal power supplies. Essentially, JBOD storage is the most basic and affordable option when it comes to combining disks for your data center.