Adaptive Mapping Tree Format Conversion for Fragmented Storage

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Solution Overview

Problem

The memory cost for extent-based address mapping schemes can exceed that of page-based schemes, particularly in workloads with frequent random writes, due to fragmentation and inefficient memory usage.

Innovation Solution

A storage system and method that calculates the average length of extents allocated to a logical address region, converting the mapping information format from extent-based to page-based or vice versa based on this average length to optimize memory usage, reducing fragmentation and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If extent-based address mapping scheme is used, then memory cost is reduced compared to page-based mapping, but memory cost increases when workload involves frequent random writes causing fragmentation

Engineering Contradiction:

Improvememory costVSAvoidadaptability to workload characteristics

Core Design Contradiction:

Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic format conversion between extent-based and page-based mapping representations based on workload characteristics. The system monitors extent allocation patterns and automatically converts the mapping format when fragmentation is detected, allowing the system to adapt to changing workload conditions rather than being fixed in one format

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the representation parameter of mapping information from extent-based to page-based format (or vice versa) based on the average extent length calculation. This parameter change allows the system to optimize memory usage under different workload conditions by selecting the appropriate representation format

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If extent-based mapping is used for all nodes, then memory efficiency is improved, but processing overhead increases due to format conversion requirements

Engineering Contradiction:

Improvememory efficiencyVSAvoidprocessing overhead

Core Design Contradiction:

Quantity of substanceVSLoss of time

Solution Approach 1:

The patent applies different mapping formats to different nodes based on their specific characteristics. Instead of uniformly applying extent-based mapping to all nodes, the system evaluates each node's extent allocation pattern and applies the most appropriate format locally, converting only when necessary rather than universally

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system performs format conversion only partially - specifically when the average extent length exceeds a threshold indicating fragmentation. Rather than continuously converting or converting all nodes, the system applies conversion selectively to nodes that benefit from it, reducing unnecessary processing overhead

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS12566698B2Storage system and operating method of of mapping conversion based on average length of extents allocated to mapping tree

Publication Date: 2026.03.03 SAMSUNG ELECTRONICS CO LTD

AI summary

A method for operating a storage system including a storage includes calculating an average length of extents allocated to a logical address region corresponding to a particular node of an address mapping tree, the address mapping tree being associated with the storage, and a mapping information format of the particular node being a first format and, based on the average length, converting the mapping information format of the particular node from the first format to a second format.