Raid 50; Raid 6; Non-Raid - HP 2000fc Reference Manual

RAID 50

RAID 50 virtual disks are made up of two or more RAID 5 virtual disks, across
which data is striped. RAID 50 virtual disks contain redundant information in the
form of parity data, which is calculated block-by-block for all user data. As in a
RAID 5 virtual disk, the parity information is distributed across the disk drives in
the virtual disk and occupies the equivalent capacity of one disk drive per RAID 5.
Data is interspersed with the parity information. If one disk drive in the virtual disk
fails, the data on the failed disk drive can be reconstructed from the parity data and
user data on the remaining disk drives. Two disk drives in one RAID 5 subset must
fail before the entire virtual disk fails.
The read performance of a RAID 50 virtual disk is excellent—better than a RAID 5
virtual disk—along with better data protection. Write performance is lower than that
of a RAID 0 virtual disk, because write operations involve calculating and writing
new parity data as well as writing the new user data.

RAID 6

RAID 6 virtual disks contain redundant information in the form of parity data,
which is calculated block-by-block for all user data. The parity information is
distributed across the disk drives in the virtual disk and occupies the equivalent
capacity of approximately two disk drives. Data is interspersed with the parity
information. If one or two disk drives in the virtual disk fail, the data on the failed
disk drives can be reconstructed from the parity data and user data on the remaining
disk drives. Three disk drives must fail before the entire virtual disk fails.
Non-sequential read and sequential read/write performance is comparable to RAID
5, however non-sequential write performance is less than RAID 5.

Non-RAID

Non-RAID virtual disks provide the ability to create a host-accessible volume
consisting of a single disk drive in the system. A Non-RAID virtual disk is
nonredundant and its capacity equals the disk drive capacity. Non-RAID virtual
disks are useful if you have a single disk drive available and you do not want to use
it as a spare.
Appendix B RAID Levels 251