File System Hole List for Compressed Extent Relocation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Inline data compression in data storage systems faces challenges when compressed data elements do not fit in allocated space, leading to frequent space reallocation and the creation of 'holes' that reduce storage efficiency and increase wear on flash devices.
Innovation Solution
The technique aggregates data into batches, compresses extents, and performs an FS-relocate operation to place compressed data into identified holes in the FS-hole list, reusing existing holes and reducing the need for frequent space allocation and garbage collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If new storage space is allocated to accommodate new compressed data, then storage capacity is maintained, but storage efficiency drops due to accumulated holes
Solution Approach 1:
The patent recovers and reuses storage space from holes by maintaining a hole list that tracks available space. When new compressed data needs to be stored, the system searches the hole list for suitable space and relocates data into these previously abandoned regions, thereby recovering unused space and preventing storage efficiency degradation.
Solution Approach 2:
The patent introduces a new dimension of space management by creating a hole list data structure that tracks and manages fragmented storage space separately from the main allocation process. This additional dimensional layer enables the system to efficiently match new data with available hole space, transforming the problem of scattered fragments into an organized resource.
2Loss of energy
If garbage collection is performed to compact holes, then storage efficiency is restored, but flash device wear increases
Solution Approach 1:
The patent performs preliminary action by proactively tracking and recording holes in a hole list as they are created during normal write operations. This advance preparation allows the system to immediately reuse hole space when needed, eliminating the need for later garbage collection operations that would cause flash device wear.
Solution Approach 2:
The system provides self-service by automatically managing hole tracking and data relocation without requiring external garbage collection interventions. The hole list mechanism enables the storage system to service its own space management needs, reducing reliance on wear-inducing garbage collection operations.
3Quantity of substance
If space allocation is performed frequently to accommodate compressed data, then data storage is maintained, but processing time increases
Solution Approach 1:
The patent performs preliminary action by pre-tracking and organizing available hole space in a hole list during normal operations. This advance preparation eliminates the need for time-consuming space search and allocation operations when new compressed data arrives, as suitable space can be immediately identified from the pre-organized hole list.
Solution Approach 2:
The patent replaces the traditional mechanical space allocation process with a more efficient information-based system. Instead of performing sequential search and allocation operations, the system uses a hole list data structure that provides direct access to available space, substituting computational efficiency for mechanical processing time.
Data Source
AI summary
A technique for writing data in a file system includes aggregating data received in a set of I/O requests into a batch that includes multiple extents of data. After compressing a current extent of the batch and determining that the compressed extent does not fit in a space where a previous version of the extent is stored, the technique performs an FS-relocate operation by accessing an F S-hole list provided for the file system and selecting a hole, from the FS-relocate list, which is large enough to accommodate the compressed extent. The technique then places the compressed extent in the selected hole.