A Method for Delayed Persistence of Index Metadata in a Flash Storage System

Abstract

The invention provides a method for delaying persistent indexing metadata in a flash memory storage system. The method for delaying the persistent indexing metadata in the flash memory storage system comprises the following steps: S1, data types and an inverted index of data are generated by the flash memory storage system when the data are written, and the inverted index is written in a flash memory together with the data; S2, a forward-direction memory index is set up according to the data, the data types and the inverted index, and data which are not written in the forward-direction memory index are marked through a list of indexes to be persistent; S3, data where forward-direction indexes are not set up are tracked through an updating window; S4, when the flash memory storage system breaks down, the forward-direction index is reconstituted according to the data types and the inverted index of the updating window so as to recover breakdowns of the flash memory storage system. According to the method for delaying the persistent indexing metadata in the flash memory storage system, because persistence of the forward-direction index is delayed through the inverted index, delay of write operations of the data is reduced, the transaction operation overhead of indexed data and the indexing metadata is avoided, and meanwhile competition delay caused by persistence of window metadata updating is reduced.

Description

technical field [0001] The invention relates to the technical field of flash memory storage, in particular to a method for delaying and persisting index metadata in a flash memory storage system. Background technique [0002] Flash memory is an electronically erasable and programmable non-volatile memory device. Flash memory is read and written in units of pages and erased in units of blocks. As the number of programming and erasing (Program / Erase, P / E) increases, the ability of the flash memory unit to store electrons is weakened, reducing the reliability of data storage. Flash memory has a limited number of times to program and erase, and this problem is also known as the lifetime problem of flash memory. [0003] In a storage system, a data write operation usually includes data update and metadata update, the latter is used to record the location of data update or record the status of data modification. For example, the operation of the file system to create a file nee...

AI Technical Summary

Problems solved by technology

Frequent metadata update persistence also causes a large number of additional flash page writes

Finally, the persistence of index metadata also complicates the atomicity guarantee of data write operations

Software modules such as file systems introduce mechanisms such as transactions to maintain the atomicity of write operations, which further aggravates the performance and lifespan of flash storage systems.

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