Tuesday, May 18, 2010

All About RAID 10

RAID 10 arrays use at least 4 hard disks (and additional disks must be added in pairs). RAID 10 works by first placing the disks into mirrored pairs at the lower level. Next, the controller selects a member from each mirrored pair and stripes the data into a new logical volume.

There are several advantages of using RAID 10 - the most important of these is the fact that it is more fault tolerant than other levels of RAID because of the mirroring of data at the lower level. The array can sustain multiple disk failures as long as an entire mirror is not lost. The biggest disadvantage is reduced capacity. For example, if you have four 500GB disks in a RAID 0 array, the total capacity would be 2TB. In a RAID 10, the total capacity would be 50% or 1TB.

As with any RAID level, problems can occur with the hard disks or controller that can cause RAID failure. The data can become lost due to a degraded RAID, rebuild failure, RAID controller failure, power failure, damage to the array configuration, hardware or software problems, or array volumes that will not mount for various reasons.

If you are experiencing RAID failure, it is important that the array remain intact. The very first thing you should do is power off the RAID server immediately to ensure no additional writes are performed. Any events describing the problem should be noted. If the member disk drives are removed, it would be helpful they are labeled in the correct order removed (but not required). More information can be found by visiting our RAID 10 recovery page. ReWave Data Recovery offers a free evaluation for RAID recovery and a no data-no fee policy. We have over 17 years of experience recovering data from all types of media including RAID.

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