DATOptic ARC-1680 Series - Manual (Page 166)

APPENDIX
166
Appendix E
RAID Concept
RAID Set
A RAID set is a group of disks connected to a SAS RAID control-
ler. A RAID set contains one or more volume sets. The RAID set
itself does not define the RAID level (0, 1, 10, 3, 5, 6, 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 SAS 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.