RAID 0 Data Recovery

Also known as a striped set, RAID 0 splits data evenly across two or more disks with no parity information for redundancy. We can recover data from these striped sets. Regardless of the problem, if you have suffered a drive failure, controller failure, or file system corruption, we can recover data from your RAID 0 array.

Many customers are utilizing this technology and they don't even realize it. RAID 0 is commonly used in 500GB+ external drives. Some of the most common of these that we get in are LaCie Big Disk and Maxtor One Touch drives. It should be noted that for any RAID 0 recovery to be successful, ALL drives must be accessible. If one drive has physically failed, then we must first get that drive funtional again so that we can image and destripe the set. If we cannot image all of the drives within the array then data corruption will be prevalent.

It is important to note that RAID 0 was not one of the original RAID levels, and is not redundant. RAID 0 is normally used to increase performance, although it can also be used as a way to create a small number of large virtual disks out of a large number of small physical ones. A RAID 0 can be created with disks of differing sizes, but the storage space added to the array by each disk is limited to the size of the smallest disk-for example, if a 120 GB disk is striped together with a 100 GB disk, the size of the array will be 200 GB. Although RAID 0 was not specified in the original RAID paper, an idealized implementation of RAID 0 would split I/O operations into equal-sized blocks and spread them evenly across two disks. RAID 0 implementations with more than two disks are also possible, however the reliability of a given RAID 0 set is equal to the average reliability of each disk divided by the number of disks in the set. That is, reliability (as measured by mean time to failure (MTTF) or mean time between failures (MTBF)) is roughly inversely proportional to the number of members-so a set of two disks is roughly half as reliable as a single disk. The reason for this is that the file system is distributed across all disks. When a drive fails the file system cannot cope with such a large loss of data and coherency since the data is "striped" across all drives.

While the block size can technically be as small as a byte it is almost always a multiple of the hard disk sector size of 512 bytes. This lets each drive seek independently when randomly reading or writing data on the disk. If all the accessed sectors are entirely on one disk then the apparent seek time would be the same as a single disk. If the accessed sectors are spread evenly among the disks then the apparent seek time would be reduced by half for two disks, by two-thirds for three disks, etc., assuming identical disks. For normal data access patterns the apparent seek time of the array would be between these two extremes. The transfer speed of the array will be the transfer speed of all the disks added together.

RAID 0 is useful for setups such as large read-only NFS servers where mounting many disks is time-consuming or impossible and redundancy is irrelevant. Another use is where the number of disks is limited by the operating system. In Microsoft Windows, the number of drive letters for hard disk drives may be limited to 24, so RAID 0 is a popular way to use more disks. It is also a popular choice for gaming systems where performance is desired, data integrity is not very important, but cost is a consideration to most users. However, since data is shared between drives without redundancy, hard drives cannot be swapped out as all disks are dependent upon each other.