Fragmented Data Storage Bands for Shingled Magnetic Recording
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Solution Overview
Problem
Shingled magnetic recording (SMR) disc drives face inefficiencies in random write operations due to the need to rewrite entire bands, leading to increased time and resource utilization, especially with larger band sizes, as sequential data writes can overwrite adjacent tracks, limiting the ability to write data randomly.
Innovation Solution
The method involves identifying sequential data streams and mapping them to open bands, allowing for virtual streams to be written directly to these bands, thereby reducing the need for full-band rewriting by using logical block addresses (LBAs) to manage data streams efficiently, especially in scenarios with high temporal locality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If shingled magnetic recording (SMR) is used to increase storage density, then storage capacity is improved, but random write operations become inefficient due to the need to rewrite entire bands
Solution Approach 1:
The patent segments the storage band into multiple zones or regions, allowing selective writing to only the necessary segments rather than rewriting the entire band. This segmentation enables more efficient random write operations by isolating the affected areas and avoiding unnecessary overwriting of adjacent tracks.
Solution Approach 2:
The patent performs preliminary actions by pre-positioning data in temporary storage areas or buffers before final write operations. This allows the system to prepare write operations in advance, reducing the impact of SMR constraints during actual write operations and improving overall write efficiency.
2Quantity of substance
If larger band sizes are used in SMR drives, then storage density is improved, but time and resource utilization for write operations increases
Solution Approach 1:
By dividing large bands into smaller manageable segments, the patent reduces the amount of data that needs to be rewritten when performing random write operations. This segmentation strategy directly addresses the time loss issue by limiting the rewrite scope to only the necessary segments rather than the entire large band.
Solution Approach 2:
The patent applies partial action by writing only to the specific portions of the band that are actually needed, rather than performing full-band writes. This approach reduces resource utilization and write operation time by avoiding excessive writing to unnecessary areas of the storage medium.
3Reliability
If sequential data writes are performed in SMR drives, then data integrity is maintained, but the ability to write data randomly is limited
Solution Approach 1:
The patent segments the storage medium into multiple zones that can be independently managed, allowing certain zones to be optimized for sequential writes (maintaining data integrity) while other zones or segments can accommodate random write operations. This segmentation provides versatility without compromising the reliability of sequential write operations.
Solution Approach 2:
The patent implements dynamic write mode selection that can adapt between sequential and random write operations based on the specific operation requirements. This dynamic approach allows the system to maintain data integrity when sequential writes are needed while also providing random write capability when required, enhancing overall adaptability.
Data Source
AI summary
An implementation of a system disclosed herein provides a method for managing data streams of sequential nature, wherein the method writes the sequential chunks (fragments) directly to an open band in the order these are received from the host and includes determining an end of the incoming data write request related to streaming data and in response to the determination of the end of the incoming data write request related to streaming data, copying remaining data from a current physical band mapped to logical block addresses LBAs related to the data write requests to the allocated (open) band.