Netgear RNRX443E – ReadyNAS 1500, 12TB NETWORK STORAGE (4 x 3 TB) Software Guide

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Understanding RAID
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ReadyNAS for Business RAIDiator 4.2.17
The Benefits of X-RAID2
X-RAID2 is a proven, NETGEAR technology for protecting your data, and is available only on 
NETGEAR ReadyNAS systems. Managing RAID volumes can be a complex chore, but 
X-RAID2 eliminates the complexity of volume management. X-RAID2 mode is an 
auto-expandable RAID technology and is the default configuration on most ReadyNAS units.
The ReadyNAS supports both X-RAID2 (the second generation X-RAID) and Flex-RAID 
(RAID 0/1/5/6) mode. Flex-RAID mode enables a more standard RAID configuration. See 
43 and 
X-RAID2 Is Auto-expandable RAID
Over time, chances are that you will need to expand volume capacity to either add 
redundancy or add more file storage space. In typical RAID systems, the steps required to 
expand volumes can be so complex and error prone that it leads to data loss. 
A major X-RAID2 advantage is its ability to automatically expand to include the full space of 
new disks. X-RAID2 enables volume expansion without reformatting your disks or shuffling 
data back and forth. X-RAID2 automates these complex tasks, and provides volume 
management features previously available only in enterprise-level storage solutions.
When as few as two of your disks have extra capacity, the data volume automatically 
expands its capacity. The data volume capacity increases every time a larger disk is added, 
regardless of the capacity of the other disks in the system. 
The process occurs in the background, so access to the ReadyNAS is not interrupted. 
Furthermore, X-RAID2 supports multiple parity, which provides protection against two 
simultaneous disk failures. 
Simplified Redundancy
X-RAID2 requires one data volume of a minimum of one disk overhead to provide 
redundancy and protect against disk failure. In a two-disk X-RAID2 volume, the usable 
capacity is one disk, in a three-disk volume the usable capacity is two disks, in a four-disk 
volume, the usable capacity is three disks, and so on.
Even with RAID, there is no data redundancy with one disk; if that disk fails, your data is lost. 
If you have a one-disk ReadyNAS 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 hot-added while the ReadyNAS is 
running.
Whenever you add or replace a disk, the ReadyNAS will initialize and scan it to make sure 
the disk is good. Once added, ReadyNAS will synchronize the new disk with the original disk. 
Depending on the disk size, the synchronization could take anywhere from 30 minutes to 
several hours. Synchronization occurs in the background so you can keep on working with 
the ReadyNAS during this time.