Storage Device Cache Compression Volume Mapping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In storage devices, updating compressed data can result in varying sizes, leading to high processing overhead as the compressed data may not fit in the original storage area, requiring complex processes like decompression and re-compression, which affects access performance.
Innovation Solution
A storage device configuration with a decompression volume and a compression volume, where data is compressed online in a cache memory and stored directly in the final storage media, maintaining mapping information to convert read requests from the decompression volume to the compression volume, allowing for efficient data access and storage without complex overwrite processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If compressed data is stored directly in the final storage media, then storage capacity efficiency is improved, but data update processing complexity increases due to size variations
Solution Approach 1:
The patent introduces a cache memory as an intermediary between the host computer and the final storage media. The cache memory temporarily stores compressed data during update operations, allowing the system to handle size variations without direct complex processing on the storage media. This intermediary buffer simplifies the update process by decoupling the compression operations from the storage operations.
Solution Approach 2:
The patent segments the storage system into multiple components: a decompression volume for host access, a compression volume for actual data storage, and a cache memory for intermediate operations. This segmentation allows each component to handle specific tasks efficiently, with the compression volume managing storage capacity independently of update processing complexity.
2Quantity of substance
If data is compressed before storage, then storage media costs are reduced, but access performance deteriorates due to compression/decompression overhead
Solution Approach 1:
The patent performs data compression in advance during the write operation, before data needs to be read. Compressed data is stored in the compression volume, and when read requests occur, the data is already in its compact form. This preliminary compression action eliminates the need for real-time compression during read operations, maintaining fast access performance.
Solution Approach 2:
The cache memory serves as an intermediary that handles decompression operations. When the host computer requests data, the cache memory decompresses the data from the compression volume and delivers it to the host. This separates the compression/decompression overhead from the host's data access operations, maintaining perceived access performance while enabling efficient storage.
3Productivity
If update data is compressed online, then processing overhead is reduced, but cache memory requirements increase
Solution Approach 1:
The patent changes the compression ratio parameter dynamically based on data characteristics and cache availability. By adjusting compression parameters, the system can optimize between processing speed and cache memory usage. For highly compressible data, higher compression ratios reduce cache requirements, while for less compressible data, lower ratios maintain processing throughput.
Data Source
AI summary
The storage device of the present invention provides a decompression VOL having no corresponding relationship (mapping) with a final storage media to a superior device, and receives accesses from the superior device to the decompression VOL. Then, data written into the decompression VOL is compressed on-line in a cache memory, and the compressed data is mapped to a compression VOL which is a volume mapped to a final storage media. At the same time, by maintaining and managing a mapping information between an area in the decompression VOL where data has been written and a location in the compression VOL to which compressed data of the relevant data is mapped, when a read request is received from a superior device regarding the decompression VOL, the storage device converts a location information in the decompression VOL designated by the read request to a location information of the final storage media.