Configuring SSDs in RAID 0 can result in some truly jaw-dropping transfer speeds. More on that at the end.
RAID 1 -- Mirroring:
RAID 1, or mirroring, also requires a minimum of two drives. But instead of striping data, the data stored on the drives in the array is duplicated across all the hard drives. RAID 1 offers a level of data redundancy, and the array can be rebuilt in the event of a drive failure without any loss of data.
Performance can also be improved somewhat, at least when using hard disk drives, since any drive in the array can be accessed to read data, and one drive may offer lower seek or rotational latency due to the position of its drive heads. Write performance is usually lowered, however, because data is mirrored to all of the drives in the array. The total capacity of a RAID 1 volume will equal the capacity of a single drive on account of the redundancy: If two 1TB drives are used, the total capacity of the RAID 1 volume will still be 1TB.
RAID 5 -- Striping with Parity:
RAID 5, which requires a minimum of three drives, improves performance by striping data like RAID 0, but it also offers a level of redundancy in RAID 1-like fashion by storing parity data across the drives in the array.
In a RAID 5 setup, a single drive in the array can fail without any loss of data, but performance will be degraded until the bad drive is replaced and the array rebuilt. Depending on the capacity of the drives used, rebuilding a RAID 5 array can take some time, so it's usually recommended for smaller volumes. Also note that the total capacity of a RAID 5 setup will be the sum of all of the capacities of the drives used in the array, minus the capacity of one. Three 1TB drives used in RAID 5, for example, will offer a total capacity of 2TB.
JBOD -- Just a Bunch Of Disks:
Technically, JBOD is not RAID, since it doesn't offer any sort of redundancy, but it is a mode supported by most drive controllers. JBOD gives users the ability to link multiple drives together to create a single, larger-capacity volume. There is no performance improvement nor data protection though. JBOD is used to simply increase the capacity of a volume; when one drive in a JBOD array is filled, data spills over to the next drive, and so on.
Prepping for RAID
There are a few things to keep in mind before setting up RAID on an existing system. If you're starting fresh with a new PC, there's no preparation needed short of making sure you've got the drives connected to the right ports on your motherboard or RAID card/controller. But on an already-configured system, there are many, many considerations.
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