Performance improved data storage and method

Abstract

A log-structured write cache for a data storage system and method for improving the performance of the storage system are described. The system might be a RAID storage array, a disk drive, an optical disk, or a tape storage system. The write cache is preferably implemented in the main storage medium of the system, but can also be provided in other storage components of the system. The write cache includes cache lines where write data is temporarily accumulated in a non-volatile state so that it can be sequentially written to the target storage locations at a later time, thereby improving the overall performance of the system. Meta-data for each cache line is also maintained in the write cache. The meta-data includes the target sector address for each sector in the line and a sequence number that indicates the order in which data is posted to the cache lines. A buffer table entry is provided for each cache line. A hash table is used to search the buffer table for a sector address that is needed at each data read and write operation.

Description

technical field [0001] The present invention relates generally to data storage devices and systems, and more particularly to log-structured write caches, to improve the performance of such devices and systems by converting random data writes to sequential data writes. Background technique [0002] Log-structured storage systems have been proposed to improve the performance of writing data by converting random writes into sequential writes. Storage devices such as hard disk devices have sequential access throughput that is orders of magnitude faster than random I / O throughput. However, log-structured storage devices and systems are costly to implement and thus have significant disadvantages. Although random writes are converted to sequential writes, sequential reads are often converted to random reads, negating any performance improvement. Journal-based file systems are often very complex to implement and manage. Ultimately, log-structured storage devices and systems canno...

AI Technical Summary

Problems solved by technology

However, this technical solution cannot obtain the performance advantage of sequential writing

[0005] Rosenblum et al. ("The Design and Implementation of a Log Structured FileSystem," ACM Transactions on Computer Systems, V10-1, Feb.1992, pp.26-52) disclose yet another prior art solution, where for performance reasons , the file system is designed to perform sequential writes, but this technical solution is only applicable to systems that can implement log-structured file systems, so it is host-dependent

Furthermore, the full performance of this system will not perform adequately unless the file system knows the underlying characteristics of the storage system, which is usually not the case

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