Whitepaper: X-RAID2 vs Flex-RAID
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IntroductIon
At NETGEAR we have received a number of questions regarding X-RAID2™ and FLEX-RAID. This whitepaper is intended to
be a simple introduction to the dierences between the two options. Before diving in, it is important to understand a few
key points:
• RAID (Redundant Array of Independent Disks) is a common storage industry term
• The primary benefit of RAID is that in multi-disk storage solutions (2-bay or greater) your data is protected
against failure of any single disk.
− At its most basic, data put on the drive is copied across all disks in the device. This is typically referred to as
“striping.” If one fails, data is still safe on the other disks. The user can then replace the bad disk and the data is
again copied and stored across all disks.
X-rAId2 is the NETGEAR version of “RAID for dummies.” This is the default and requires no knowledge or configuration to
get the protection from disk failure discussed above. With X-RAID2 you can also add disks and the additional capacity
is added to the RAID group regardless of the initial number of disks.
FlexrAId is the NETGEAR version of “RAID for experts/geeks.” You have greater flexibility and can improve capacity/
eciency/etc., but you should have a working knowledge of RAID architectures and concepts. Expansion can happen
only by adding a new RAID group of at least two disks.
X-rAId2
X-RAID2 is an auto-expandable RAID technology that is available only on ReadyNAS® systems. With X-RAID2, you do not
need to know intricate details about RAID to administer your system. X-RAID2 allows you to add storage space without
reformatting your drives or moving your data to another location. Because the expansion happens online, you can continue
to use your ReadyNAS system while the volume capacity increases.
Because X-RAID2 is a single-volume architecture, if you configure your hard disk drives to use X-RAID2, your storage
system has only one volume that is made up of all installed hard disk drives. X-RAID2’s single-volume architecture has two
major advantages:
• Easy system management
• Auto-expansion
With X-RAID2, you can start out with one hard disk, add a second disk for data protection, and add more disks for
additional storage capacity. X-RAID2 accommodates the new disks automatically. You can replace existing disks with
larger-capacity disks and X-RAID2 automatically accommodates the new disks.
X-RAID2 requires a minimum of two hard disks to provide protection against disk failure. If you have a one-disk ReadyNAS
storage system and want protection from disk failure, you must add a second disk that is at least as large as the first. It can
be added while the system is running.
X-RAID2 uses the capacity of one disk for data storage and reserves the capacity of a second disk for data protection,
which allows the volume to recreate data if a disk fails. In a two-disk system, the usable storage space is one disk. In a
three-disk system, the usable storage space is two disks. In general, the total capacity of your storage system equals the
capacity of all your disks minus the capacity of one disk.
X-RAID2 also allows for the automatic expansion of volume size when you replace a disk drive with a larger capacity drive.
Detailed instructions are available in the soware manual.