Memory Controller Meta-Data Segmentation for Power Loss
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Solution Overview
Problem
Data storage devices face challenges in stably storing meta-data and user data during sudden power-offs, requiring efficient management of mapping relationships between logical and physical addresses, and minimizing the capacity of auxiliary power sources.
Innovation Solution
A data storage device with a memory controller that generates and stores meta-data in normal and modified meta-slices, along with context data, to facilitate efficient data restoration during power-on modes, utilizing a meta-data flush circuit for periodic data management and a meta-data rebuild circuit for data reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the capacity of the auxiliary power source is increased to flush more data in sudden power-off situations, then the reliability of data storage is improved, but the cost and size of the auxiliary power source increases
Solution Approach 1:
The meta-data is divided into multiple meta-slices, each stored in separate meta-pages. During normal operation, only essential meta-slices are flushed to storage, while less critical portions remain in volatile memory. This segmentation allows the system to maintain data reliability without requiring the auxiliary power source to support flushing of the entire meta-data set simultaneously.
Solution Approach 2:
Different portions of meta-data are assigned different priority levels for flushing. Critical meta-data (such as mapping information essential for system boot) is marked for guaranteed flushing, while less critical portions are flushed only when power conditions permit. This local quality differentiation optimizes the use of auxiliary power source capacity.
2Reliability
If all meta-data is flushed to storage during sudden power-off, then data reliability is improved, but the power consumption and time required for flushing increases
Solution Approach 1:
Instead of flushing the entire meta-data set during sudden power-off events, the system performs partial flushing of only the most critical meta-slices. This partial action approach ensures that essential data is preserved while avoiding the excessive power consumption and time requirements of flushing all data.
Solution Approach 2:
The system implements a selective flushing mechanism that skips non-critical meta-data portions during power-off events. By rushing through the identification and flushing of only essential meta-slices, the system achieves reliable data storage with reduced power consumption and faster completion time.
3Loss of energy
If the size of meta-slice is reduced to minimize flushed data, then auxiliary power source efficiency is improved, but the number of meta-pages required increases
Solution Approach 1:
The meta-data is segmented into fixed-size meta-slices that are grouped into meta-pages. This segmentation structure allows the system to manage smaller units of data for flushing, improving power efficiency, while the meta-page organization provides a hierarchical structure that limits the overall complexity by grouping slices into manageable pages.
Solution Approach 2:
Meta-slices are nested within meta-pages, creating a hierarchical structure. This nesting allows the system to manage individual slices for efficient flushing operations while organizing them into pages for streamlined storage and retrieval, thereby reducing the operational complexity despite the increased number of individual slices.
Data Source
AI summary
A data storage device includes a storage and a memory controller. The storage is configured to store data. The memory controller generates meta-data including a mapping relationship between a logical address used in an external device and a physical address used in the storage. The memory controller generates a normal meta-slice having a first size including the meta-data in a first operation mode. The memory controller stores a meta-page including the normal meta-slice in the storage. The memory controller generates a modified meta-slice having a second size as a part of the normal meta-slice in the second operation mode. The memory controller stores a meta-page including the modified meta-slice and context data corresponding to size information of the modified meta-slice in the storage. The memory controller restores the meta-data based on the context data in a power-on mode.