RAID Information.

Raid 0

A logical drive with RAID 0 includes two or more disk drives and provides data
striping, where data is distributed evenly across the disk drives in equal-sized
sections. However, RAID 0 arrays do not maintain redundant data, so they offer no
data protection.
Compared to an equal-sized group of independent disks, a RAID 0 array provides
improved I/O performance.
Drive segment size is limited to the size of the smallest disk drive in the logical
drive. For instance, a logical drive with two 250 GB disk drives and two 400 GB disk
drives can create a RAID 0 drive segment of 250 GB,


Raid 1

A RAID 1 logical drive is built from two disk drives, where one disk drive is a mirror
of the other (the same data is stored on each disk drive). Compared to independent
disk drives, RAID 1 logical drives provide improved performance, with twice the
read rate and an equal write rate of single disks. However, capacity is only 50
percent of independent disk drives.
If the RAID 1 logical drive is built from different-sized disk drives, drive segment
size is the size of the smaller disk drive,


Raid 1E

A RAID 1 Enhanced (RAID 1E) logical drive—also referred to as a striped mirror—is
similar to a RAID 1 logical drive except that data is both mirrored and striped, and
more disk drives can be included. A RAID 1E logical drive can be built from three or
more disk drives.


Raid 5

A RAID 5 logical drive is built from a minimum of three disk drives, and uses data
striping and parity data to provide redundancy. Parity data provides data protection,
and striping improves performance.
Parity data is an error-correcting redundancy that’s used to re-create data if a disk
drive fails. In RAID 5 logical drives, parity data (represented by Ps in the next
figure) is striped evenly across the disk drives with the stored data.


Raid 5EE

A RAID 5EE logical drive also referred to as a hot spare is similar to a RAID 5
logical drive except that it includes a distributed spare drive and must be built from a
minimum of four disk drives.

A RAID 5EE logical drive protects your data and increases read and write speeds.
However, capacity is reduced by two disk drives’ worth of space, which is for parity
data and spare data.


Raid 6

A RAID 6 logical drive—also referred to as dual drive failure protection—is similar to a
RAID 5 logical drive because it uses data striping and parity data to provide
redundancy. However, RAID 6 logical drives include two independent sets of parity
data instead of one. Both sets of parity data are striped separately across all disk
drives in the logical drive.
RAID 6 logical drives provide extra protection for your data because they can
recover from two simultaneous disk drive failures. However, the extra parity
calculation slows performance (compared to RAID 5 logical drives).
RAID 6 logical drives must be built from at least four disk drives. Maximum stripe
size depends on the number of disk drives in the logical drive


Raid 50

A RAID 50 logical drive is built from at least six disk drives configured as two or
more RAID 5 logical drives, and stripes stored data and parity data across all disk
drives in both RAID 5 logical drives. The parity data provides data protection, and striping improves performance. RAID50 logical drives also provide high data transfer speeds.


Raid 60

Similar to a RAID 50 logical drive a RAID 60 logical drive—also referred to as dual drive failure protection— is built from at least eight disk drives configured as two or more RAID 6 logical drives, and
stripes stored data and two sets of parity data across all disk drives in both RAID 6 logical drives.
Two sets of parity data provide enhanced data protection, and striping improves performance.
 RAID 60 logical drives also provide high data transfer speeds.