Raid 1N:; Raid 10N - American Megatrends StorTrends 1100-P User Manual

RAID 0 provides disk striping across all hard disk drives in the volume. RAID 0 does not
provide any data redundancy, but does offer the best performance of any RAID level.
RAID 0 breaks up data into smaller blocks and then writes a block to each hard disk drive
in the volume. The size of each block is determined by the stripe size parameter, set
during the creation of the RAID set. RAID 0 offers high bandwidth.
By breaking up a large file into smaller blocks, StorTrends® iTX software can use
multiple IDE/SCSI channels and hard disk drives to read or write to the file faster. RAID
0 involves no parity calculations to complicate the write operation. This makes RAID 0
ideal for applications that require high bandwidth but do not require fault tolerance.
RAID 1
RAID 1 duplicates all data from one hard disk drive to a second hard disk drive. RAID 1
provides complete data redundancy, but at the cost of doubling the required data storage
capacity.

RAID 1n:

RAID 1n, or n-way mirroring; mirrors the data stored in one hard drive to several hard
drives. This array type provides superior data redundancy because there are three or more
copies of the data, and is useful for creating exact copies of an array for backup purposes.
However, this array type is expensive, in both performance and the amount of disk space
necessary to create the array type.
RAID 5
RAID 5, also known as a stripe with parity, stripes data as well as parity across all drives
in the array. Parity information is interspersed across the drive array. In the event of a
failure, the controller can restore the lost data of the failed drive from the other surviving
drives. This array type offers exceptional read performance as well as redundancy. In
general, write performance is not an issue due to the tendency of operating systems to
perform many more reads than writes. This array type requires only one extra disk to
offer redundancy. For most systems with four or more disks, this is the correct choice as
array type. Because of this, RAID 5 is best suited for networks that perform a lot of small
I/O transactions simultaneously.
RAID 5 addresses the bottleneck issue for random I/O operations. Since each hard disk
drive contains both data and parity numerous writes can take place concurrently. In
addition, robust caching algorithms and hardware based exclusive-or assist make RAID 5
performance exceptional in many different environments.
RAID 10
RAID10 is also known as RAID (0+1) or striped mirror sets. This array type combines
mirrors and stripe sets. RAID10 allows multiple drive failures, up to 1 failure in each
mirror that has been striped. This array type offers better performance than a simple
mirror because of the extra drives. RAID10 requires twice the disk space of RAID0 to
offer redundancy.

RAID 10n

RAID 10n stripes multiple n-way mirror sets. RAID 10n allows multiple drive failures
per mirror set, up to n-1 failures in each mirror set that has been striped, where n is the
number of drives in each mirror set. This array type is useful in creating exact copies of
an array's data using the split command. This array type offers better random read
performance than a RAID 10 array, but uses more disk space.
Glossary 147