Western Digital ShareSpace User Manual page 62

Manage RAID
Configure RAID on the hard drives using the Manage RAID tab on the Volume
Management submenu.
WARNING! Changing the RAID configuration causes all volumes and
data to be lost.
RAID (Redundant Array of Independent Drives) refers to an array of multiple
independent hard drives that provide high performance and reliability. RAID function
depends on the number of drives present and the RAID level selected.
The network storage system supports the following RAID levels:
• Stripe (RAID 0) - Provides data striping (spreading out blocks of each file
across multiple hard drives) but no redundancy. This improves performance but
does not deliver fault tolerance. If one drive fails then all data in the array is lost.
• Mirror (RAID 1) - Provides disk mirroring. Mirroring creates an exact copy (or
mirror) of a set of data on two drives, which increases reliability on a single drive.
If either drive fails, the other continues to function as a single drive until the failed
drive is replaced. Note this RAID type has the highest disk overhead (100%) of all
RAID types.
• Span (JBOD) - Combines drives into a linear fashion to create one large logical
volume. It provides no fault tolerance, nor does it provide any improvements in
performance compared to the independent use of its constituent drives. Span
(JBOD) of two disk partitions as a single large partition.
• RAID 5 - Requires a minimum of 3 drives to implement. Adds fault tolerance by
including parity information with the data. Parity for blocks in the same rank is
generated on Writes, recorded in a distributed location, and checked on Read.
WD SHARESPACE
USER MANUAL
NETWORK STORAGE MANAGER - 57