You know the feeling, you go scavenging among your old disks to see if there's something useable, but mostly the individual disks are too small. Its just a bunch of old disks.
JBOD rectifies that problem, by allowing you to use the disks as if they were one single volume. The proper term is spanning, but most people call it JBOD (Just a Bunch Of Disks) in contrast to RAID (Redundant Array of Inexpensive Disks). So wherein lies the difference between JBOD and RAID 0 (striping) you might ask. Well JBOD can be thought of, as the opposite as RAID - in a RAID you partition the disks, which usually chops them up into smaller pieces, in a JBOD you combine the disks into a larger logical volume. But neither RAID 0 nor JBOD provides any fault tolerance. In fact JBOD only has 2 advantages over RAID 0:
- Its avoiding drive waste
- Easier disaster recovery
Now enter ZFS into the equation, which is designed from the assumption that all disks will eventually fail. It has excellent data-loss detection mechanisms and it can even detect silent data corruption. With ZFS your disks are stored in pools and the mount points share the same pool, which means, that its harder to run out of space. You can always add more disks to the pool without having to reshuffle your data - that's neat!
There is a really great interview with the inventors of ZFS (Jeff Bonwick and Bill Moore) on the web. Its 45 min, watch it if you have the time.
