Monday, December 19, 2011

Can one recover data from a failed drive in RAID 0 array?

RAID stands for redundant array of independent disks. There are various RAID implementations, some built for boosting the performance, some for increasing the redundancy of the data and some others for achieving both. RAID 0 is built solely for performance boosting. In RAID 0, the data is split in to stripes and is stored independently on different drives. The data is read or transferred parallely and this increases the speed of RAID 0 system. Basically, for such a system, redundancy or fail safe is zero or does not exist. In RAID 0, error checking is not implemented. So, one cannot check for errors in his data in a RAID 0 system.
More number of drives increases the speed with which one can access or write data incredibly. But if even one drive fails in a RAID 0 system, the entire information stored on all the three drives is lost because the data is stored in divided blocks. To put it simply, if you are storing a movie file on a RAID 0 system, some part of the movie is stored on drive one, some of it is stored on other drive and remaining part on remaining drives. So, even if one drive fails, one part of your movie is destroyed. And as a result, the integrity of your movie file is disrupted. So, you cannot play the file.
RAID 0 implementation is used in gaming servers where there is no need for a failsafe, but the only need is higher speed. If you notice that one hard drive among your RAID 0 system is failing, you should immediately back up the drive, or remove the drive from RAID 0 system by copying the data on that drives to other drives of RAID 0 system. In this way, one can protect their data from a hard disk failure. In case of a failed hard drive in a RAID 0 system, it is not impossible to recover the data but it is not even easy. The data from the failed hard drive disks can be collected by specialized professionals and some softwares. Then that data can be added to the existing RAID 0 system.
There are other RAID implementations like RAID 1, 2, 3 and so on till 6. Some of these are built strictly for data security such as RAID 1. This implementation needs at least two identical hard drives. RAID 1 mirrors the data stored on one drive on to the other, so that in case of failure, a back-up is immediately available.

By: Sandeep Mahanthi

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