Concatenated disk set

A concatenated disk set, also called Just a Bunch of Disks (JBOD) or spanning, is a single large disk created from several smaller disks. A concatenated disk set acts as one large disk, with the combined capacity of all the smaller disks.

A concatenated disk set is helpful if you have a file, such as a database, that’s larger than any of your disks. It’s also useful if you need to create a mirrored or striped RAID set with one large disk and two smaller disks.

If all the disks in the set are about the same size, consider using a striped RAID set, which lets you access your data more quickly.

After you create a concatenated disk set, you can use Disk Utility to add more disks to it to increase its size.

You can’t use some disk management features, such as FileVault disk encryption, with concatenated disk sets.