Method for recovering disk cache power down based on novel nonvolatile storage

Abstract

Provided is a method for recovering disk power down based on a novel nonvolatile storage. According to the method, a Linux Kernel Device Mapper frame is adopted, an AEP is adopted in cache equipment in the bottom layer, open source software dm-cache is adopted as a chief source, on the basis of achieving disk cache basic functions, a power down recovering module is added, a byte writing method is adopted to timely write metadata of a cache equipment control structure and a cache block back to a cache control block and a metadata area of the AEP so as to retain in real time an operational scene of the cache module. When power down occurs in a system accidentally and the system is restarted, the operational scene of the cache module can be recovered through the method of reloading a total control data structure which is stored in the cache equipment in the cache control block of the AEP and the metadata information of the cache block in the metadata area of the AEP so as to make the system operate at a sate before the power down, and in this way, the purpose of recovering the data in the disk cache block is achieved.

Description

technical field [0001] The invention belongs to the technical field of disk cache power failure recovery under Linux operating system, relates to the secondary development of open source disk cache software dm-cache, and specifically relates to the development of a Linux Kernel Device Mapper framework, based on dm-cache, based on A power-off recovery method for a disk cache of a new non-volatile memory AEP (Apache Pass, a non-volatile memory developed by Intel Corporation). Background technique [0002] In a typical computer system, it takes 250,000ns to sequentially read 1MB of data from the memory, and 30,000,000ns to read 1MB of data from the disk. The speed difference between the two is more than a hundred times. Imagine that in an application scenario with a heavy disk I / O load, it only takes one unit of time for data to be exchanged between the CPU and the memory, but it takes one hundred units of time for the data to be transferred between the memory and the disk. ex...

AI Technical Summary

Problems solved by technology

Before the 1980s, in a computer system without a cache, the contradiction between the high-speed processing capability of the CPU and the low-speed access speed of the memory caused the CPU to often need to suspend the execution of instructions to wait for the memory to complete data access. It seriously wastes the computing resources of the computer and reduces the overall performance of the computer system

However, after an unexpected power failure of the system, the dirty data in the cache cannot be written back to the disk due to the loss of the corresponding relationship with the cached disk blocks, resulting in a large amount of data loss

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