What Is Raid - D-Link DNS-321 User Manual

Section 3 - Configuration

What is RAID?

RAID, short for Redundant Array of Independent Disks, is a combination of two or more disks with the aim of providing fault tolerance and
improving performance. There are several different levels of RAID, with each providing a different method of sharing or distributing data
amongst the drives. The DNS-321 supports RAID levels 0 and 1.
RAID 0
RAID 0 provides data striping, which spreads out blocks of data over both drives, but does not provide data redundancy. Although
performance is improved, the lack of fault tolerance means that if one drive fails, all data in the array will be lost.
RAID 1
RAID 1 provides mirroring over both disks, with the same read/write speed of a single disk. A RAID 1 array can only be as large as it's
smallest member disk. Because the data is stored on both disks, RAID 1 provides fault tolerance and protection, in addition to performance
advantages.
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