D-Link ShareCenter DNS-340L User Manual page 434

Section 5 - Knowledge Base
RAID 1 - allows you to assign two disks as a mirrored set. Once you create the
mirrored set, you will see it as a single disk drive. But when you write data to
the mirrored set, it will duplicate the data across all members of the set. This
ensures that your data is protected against loss if any hard drive in the RAID
1 set fails. In fact, as long as any single member of the set remains functional,
you will continue to operate normally, with complete access to your data.
RAID 5 - Raid 5 combines space from three of your hard drives and uses the
fourth drive as a parity drive. Your Raid 5 volume can only be as large as three
times your smallest drive. For example, when using one 500GB, two 250GB
and one 80GB drive your largest Raid 5 volume can not exceed 240GB. In the
event that one of your hard drives fails, the fourth parity drive will be used to
rebuild your Raid.
RAID 10 - With Raid 10 the drives are mirrored for redundancy and help
optimize reading from storage. This option protects data against loss from
non-adjacent disks and benefits from the disk striping technique to speed up
operation when retrieving data from disk storage. Raid 10 requires 4 drives in
order to operate correctly and allows up to 2 drives to fail before loss of data.
D-Link ShareCenter DNS-340L User Manual 432