The difference between raid3 and raid5

RAID3: Parallel transfer with parity

RAID5: Independent disk structure with distributed parity                                                                                         (Recommended learning: phpstorm)

RAID3 uses a relatively simple verification implementation, using dedicated disks to store all parity data, and creating reads of striped data in the remaining subsets. write operation.

The difference between RAID5 and RAID3 is that RAID5 does not store all check blocks in dedicated check disks, but spreads them across all data disks. RAID 5 uses a special algorithm to calculate the storage location of any stripe check block.

RAID5 data recovery method

For general RAID data recovery, we need to understand the following parameters: disk order, block size, rotation mode and data boot sector district.

Therefore, RAID5 data recovery is also a process of determining these four parameters through the file system, file format, other related data in the disk, etc.

After determining these four parameters, the data scattered on each disk can be restored to the actual data in RAID 5 through relevant tools, thereby achieving the purpose of restoring the data in RAID 5.

The following is the general process of RAID5 data recovery:

Find the MBR and DBR through this tool, and determine whether the data in the hard disk is synchronized - >Determine by the location of the MBR The location of the starting sector - > Find the location of the MFT record of the NTFS partition through DBR - > Determine the block size and disk order through the MFT record, rotation mode - > Data reorganization, data recovery within RAID5.

Raid 3 The data stored on the N1th hard disk is verification and fault tolerance information, and every time the data is modified, data needs to be written to this hard disk, which creates a bottleneck.

RAID 5 does not back up the stored data, but stores the data and corresponding parity information on each disk that makes up RAID5, and the parity information and corresponding data are stored in different disks. on the disk.

When one disk data of RAID5 is damaged, the remaining data and corresponding parity information are used to recover the damaged data.

Raid5 can ensure that every hard disk is working every time the data is modified, so the performance is higher than Raid3.

Therefore, Raid5 is more suitable for server applications than Raid3. Both have error checking and are relatively stable Raid solutions.

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