Rapid dilatation method for RAID 5 (redundant array of independent disks)

Abstract

The invention discloses a rapid dilatation method for an RAID 5 (redundant array of independent disks). The rapid dilatation method comprises the following steps: a strip group size SS, a dilatation read unit size RU, a dilatation write unit size WU and auxiliary variables Y and St are obtained; a current dilatation window W_no is initialized to be 0; the offset w_off in the current dilatation window is initialized to be 0; a migration record set required for dilatation is set to be empty; a current disk counter d is initialized to be 0; a strip number s is obtained through s=w_no*Wsize+w_off, and the offset in the strip group is obtained through s_off=s%SS; an initial strip number Rb of a current disk dilatation read unit is obtained through Rb=d*St, and an end strip number Re is obtained through Re=Rb+RU-1; whether a strip corresponding to the strip number s exists between the initial strip number and the end strip number of the dilatation read unit of the strip group or not is judged, if not, whether d=n-1 exists or not is judged, if so, whether w_off=Wsize-1 or s=v-1 exists or not is judged, if so, a corresponding strip unit is read from a disk in the RAID 5 before dilatation and is then written into the corresponding newly-added disk. With the rapid dilatation method, the performance and storage efficiency of the array after dilatation are improved.

Description

Technical field [0001] The invention belongs to the field of data storage, and more specifically, relates to a rapid expansion method of a redundant array of independent disks RAID5. Background technique [0002] Redundant array of independent disk (Redundant array of independent disk, referred to as RAID) technology is a storage system architecture proposed by Patterson et al. in 1988. The basic idea is to combine multiple disks to improve concurrent access performance through striping technology; to improve the reliability of the storage system by storing mirrored data or parity. According to the different organization methods, RAID is divided into multiple levels. The more commonly used levels are RAID1, RAID5, etc. [0003] Such as figure 1 As shown, RAID5 uses a striping method to evenly distribute data and parity information to each disk in the array. When a disk fails, you can read the data block and parity block information on the remaining disks, and then The data on the...

AI Technical Summary

Problems solved by technology

Although this method makes the data and checksums evenly distributed, but because the original data is still only stored on the original disk, the performance cannot be improved due to capacity expansion.

In the United States Patent Application Publication US8239622, an array capacity expansion method that can be used for RAID5 is disclosed. This method minimizes the amount of data migration caused by capacity expansion by reorganizing the data layout, and satisfies the requirement that the data be evenly distributed in each disk, however this approach does not improve the storage efficiency of the array

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