DATOptic RM12-S6.TB - Rackmount - Manual (Page 73)

APPENDIX
182
Appendix E
RAID Concept
RAID Set
A RAID set is a group of disks connected to a RAID controller. A
RAID set contains one or more volume sets. The RAID set itself
does not define the RAID level (0, 1, 1E, 3, 5, 6, 10, 30, 50 60,
etc); the RAID level is defined within each volume set. Therefore,
volume sets are contained within RAID sets and RAID Level is de-
fined within the volume set. If physical disks of different capaci-
ties are grouped together in a RAID set, then the capacity of the
smallest disk will become the effective capacity of all the disks in
the RAID set.
Volume Set
Each volume set is seen by the host system as a single logical
device (in other words, a single large virtual hard disk). A volume
set will use a specific RAID level, which will require one or more
physical disks (depending on the RAID level used). RAID level
refers to the level of performance and data protection of a volume
set. The capacity of a volume set can consume all or a portion of
the available disk capacity in a RAID set. Multiple volume sets can
exist in a RAID set. For the RAID controller, a volume set must be
created either on an existing RAID set or on a group of available
individual disks (disks that are about to become part of a RAID
set). If there are pre-existing RAID sets with available capacity
and enough disks for the desired RAID level, then the volume set
can be created in the existing RAID set of the user’s choice.