How many of you are using x raid ? .. fantastic isn't it ?

We have used many xRaids in our xSan for many years and still they work great in24/7 as expected! and fantastic as you said :)

X-RAID is an auto-expandable RAID technology that is available only on ReadyNAS systems. With X-RAID, you do not need to know intricate details about RAID to administer your system. X-RAID 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-RAID is a single-volume architecture, if you configure your hard disk drives to use X-RAID, your storage system has only one volume that is made up of all installed hard disk drives. X-RAID's single-volume architecture has two major advantages:

• Easy system management
• Auto-expansion

With Flex-RAID formatting, if you want to add disks to expand your storage capacity, you must back up the data to another system, add a disk, reformat the RAID volume, and restore the data to the new RAID volume. With X-RAID, none of those administrative tasks are required. Instead, with X-RAID, your volume automatically expands to accommodate additional disks or larger-capacity disks.

With X-RAID, you can start out with one hard disk, add a second disk for data protection, and add more disks for additional storage capacity. X-RAID accommodates the new disks automatically. You can replace existing disks with larger-capacity disks and X-RAID automatically accommodates the new disks.

X-RAID 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 need to add a second disk that is at least as large as the first. It can be added while the system is running.

X-RAID 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.

The following figure illustrates how X-RAID uses new disks.

a. The first disk that you install is used for initial (unprotected) storage space.b. The second disk that you install is reserved for data protection (parity information).c. Installing additional disks increases your storage space.