Server RAID data Recovery success story and the principle of RAID 5 data recovery algorithm

Server RAID 5 Data recovery case
This shared case is a RAID disk array in a server, with 12 disks in the disk array, a single-disk capacity 500g,ext3 file system, and a Linux platform for the system platform. Raid in 2nd and 6th, two hard disks reported yellow lights, management personnel after the check on the 6th plate has been forced on-line operation, forced on-line found that most of the directory can not open, there are some directories in the directory in which file loss occurs. The customer contacted the North Asia Data Recovery Center for data recovery of the RAID disk array.

1. First analysis of the original RAID structure, the force on-line 6th to remove the disk, the 2nd plate into the virtual environment to build a raid platform.
2. Then through the software to extract the auxiliary data, after extracting the data in the 2nd plate found irregular bad way.
3. We have selected a common image tool to carry out the full image of the 2nd hard drive, more than 90% of the bad word successfully read.
4. Add the good image data to the virtual RAID environment, extract the data again, and more than 99% of the data are fully recovered.
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Principles of Raid 5 Data Recovery Algorithm * * * *
To understand the principle of RAID 5 data recovery first understand RAID5, the distributed parity of the independent disk structure (what we call RAID 5) data recovery has a "parity" concept needs to understand. We can simply understand it as an "XOR operation" in binary operations, usually using an XOR identity. The rule for this operation is that if the values are the same, the result is 0, and if the results are different, the result is 1.
For example, 0101 xor 0010 is calculated according to the above operation rules, both the first digit is 0, the same, the result is 0; 第二、三、四位 has a different value, the result is 1, so the final result is 0111, expressed as: 0101 xor 0010 = 0111, so in a XOR If one of these is missing in b=c, we can extrapolate it through other data, which is all the secret of RAID5 data recovery, and it's no problem to know that the RAID 5 data is lost after you recover the data.

Server RAID data Recovery success story and the principle of RAID 5 data recovery algorithm