Method and system for recovering mapping table after abnormal power failure of solid-state disc

Abstract

The invention discloses a method and system for recovering a mapping table after abnormal power failure of a solid-state disc. Snapshot fragment pages are divided into odd-number snapshot fragment pages and even-number snapshot fragment pages according to the page parity of stored logic page modification data and are stored in an odd-number channel and an even-number channel in a flash memory respectively; when power failure recovers from the solid-state disc, mapping information stored during abnormal power failure and the mapping table stored in the flash memory the last time before abnormal power failure are read from the flash memory; the mapping information comprises location information of the mapping table stored the last time and start-stop addresses of snapshot fragment pages stored in the flash memory after the moment when the mapping table stored the last time begins to be written in the flash memory; N CPUs (central processing units) read the mapping table stored the last time according to the start-stop addresses and update the mapping table stored the last time according to the odd-number snapshot fragment pages and the even-number snapshot fragment pages respectively, and N is an even number. The parallel processing degree during recovery of power failure can be enhanced, and the power failure recovery time is further shortened.

Description

technical field [0001] The invention relates to the technical field of snapshots, in particular to a method and system for restoring a mapping table after a solid state disk is powered off abnormally. Background technique [0002] With the advancement of NAND flash memory technology, the capacity of solid-state disks (including multiple flash memory chips in solid-state disks) is getting larger and larger, and the metadata of solid-state disks, especially the mapping table, is also getting larger and larger. As a result, the mapping table loses a lot of important data. At present, it is generally used to increase the capacitor to prolong the power-down time, and at the same time use the snapshot technology to save the snapshot segment with the changed mapping information to the flash memory. [0003] Wherein, the snapshot technology refers to taking a snapshot of information in a mapping table from a logical page to a physical page. The normal working process of the solid-s...

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Problems solved by technology

[0004] However, at present, when the power-off recovery is performed on the mapping table, the problem of long recovery time often occurs due to the large amount of data to be recovered, and the reliability is low.

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