User`s manual

DC-200 RAID card User’s Manual
E42/E43
9. Glossary about DC-200 RAID card functions
RAID:
Abbreviation of Redundant array of independent disks. It is a set of disk
array architectures that provides fault-tolerance and improve performance.
RAID 0(striping):
An array where data is distributed, or striped , across the disks in the
array.
If 2 HDDs are configured as RAID 0, data can be processed into 2
HDDs simultaneously to double system throughput rate, if 4 HDDs are
configured as RAID 0, data can be processed into 4 HDDs simultaneously
to make system throughput rate 4 folds. It offers the best performance but
no fault-tolerance. The capacity of RAID 0 will be double the size of the
smaller HDD when 2 HDDs create one RAID 0 and 4 times the size of the
smallest HDD when 4 HDDs create one RAID 0, so we suggest you connect
HDDs of the same sizes to save HDD space.
RAID 1(mirroring):
An array which uses a single pair of disks. Both disks in the pair contain the
same data It provides the best data protection but can’t improve system
performance. And storage space for the same data capacity should be double
than in general cases. Hence storage cost doubles. The capacity of RAID 1
will be the size of the smaller HDD, so we suggest you connect HDDs of the
same sizes to save HDD space.
RAID 0+1(striping and mirroring):
When 4 HDDs are configured as RAID 0+1, it will do striping and
mirroring simultaneously, hence, it has double function of increasing system
performance and enhancing data safety. But storage space for the same data
capacity should be double than in general cases. Hence storage cost doubles.
The capacity of RAID 0+1 will be double the size of the smallest HDD, so we
suggest you connect HDDs of the same sizes to save HDD space.
Rebuild:
In RAID 1 or RAID 0+1 mode, if one HDD fails, it can be replaced with a
workable HDD to restore data and recover RAID array to protect data safety.
JBOD: