Cache method for file system with changeable data block length

Abstract

The invention relates to a cache method for a file system with changeable data block length, belonging to the technical field of computer data storage. The method of the invention comprises the following steps: intercepting operating commands from a computer application program by a driving module of a user state file system, wherein the operating commands comprises opening the existing files, reading data from the opened files, writing data into the opened files, modifying the file attributes and closing the opened files; operating a cache management module in a daemon process mode; and temporarily saving partial data which is read and written recently in each currently opened file into data blocks with random length in the internal storage of a computer, thereby reducing the frequency of access of the file system to external storage devices, and improving the efficiency and throughput of accessing data in the file system. The method of the invention can enable the data reconstruction and data segmenting processes to be transparent to the user and computer application programs, thereby enabling the file system to support a repeating data deleting function under the condition that the compatibility is not affected, and effectively improving the utilization efficiency of the physical storage space.

Description

technical field [0001] The invention relates to a file system caching method with variable data block length, which belongs to the technical field of computer data storage. Background technique [0002] The file system is an important part of the computer system. It is responsible for organizing, managing and storing files on external storage devices (such as hard disks, U disks, etc.) to achieve persistent storage of data. However, it is not an efficient and wise choice to store data directly on external devices: first, external storage devices cannot support random read and write data at byte granularity like internal memory (RAM). block) as the basic operation unit for reading and writing data, a block usually includes thousands or even hundreds of thousands of bytes; moreover, the speed of data access (I / O) of external storage devices is generally several orders of magnitude slower than that of internal storage It is far behind the speed of CPU processing data and has b...

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Problems solved by technology

[0005] Obviously, the file system cache management method based on fixed-length blocks cannot effectively adapt to the above-mentioned data operation characteristics of variable-length block segmentation based on file content, because when re-segmenting the modified data in the cache based on content, it needs The data to be split is placed in a continuous memory space. For this reason, the file system cache based on fixed-length blocks will require a large number of memory allocation and data movement operations, which is inefficient, complicated to manage, and poor in stability.

[0006] Due to the inherent defects of the fixed-length block file system caching method in supporting data deduplication, many systems that use the idea of ​​deduplication to reduce network bandwidth overhead, such as the " A Low-Bandwidth Network File System” system and the WAN data backup and synchronization system Dropbox, etc., all need to save a complete copy of the operated file on the client, regardless of whether the file copy is reconstructed by data blocks or the modified file copy is re-divided into Data blocks consume a lot of storage and computing resources, which is an inefficient implementation method

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