Shingled Magnetic Recording Burst Write Verification
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Solution Overview
Problem
Data storage devices employing shingled magnetic recording (SMR) technology face slowdowns and verification challenges when handling many random write operations due to the need for data verification during burst writes, which can lead to interruptions and difficulties in rewriting data due to the high density and overlapping tracks.
Innovation Solution
Implementing a cache storage region that accumulates write data until a commit threshold is reached, followed by burst transferring it into SMR storage regions divided into zones, with verification performed only after the burst transfer is complete, and writing data with verification errors to an exception location within the same zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data verification is performed during each write operation in SMR storage, then data integrity is maintained, but write performance deteriorates due to frequent verification interruptions
Solution Approach 1:
The patent accumulates multiple write operations in a cache buffer before performing a single verification operation. This preliminary accumulation of data allows the system to defer verification until after a batch of writes is complete, reducing the frequency of verification interruptions and improving overall write performance while still maintaining data integrity through the final verification step.
2Quantity of substance
If SMR storage handles many random write operations, then storage capacity utilization is improved, but write speed deteriorates due to verification slowdowns
Solution Approach 1:
The patent segments the SMR storage medium into multiple zones, allowing different write operations to be directed to different zones. This segmentation enables parallel processing of write operations across multiple zones, reducing the impact of verification slowdowns on overall write speed while maintaining high storage capacity utilization.
3Reliability
If data is rewritten in SMR storage after verification errors, then data correctness is restored, but operation complexity increases due to track overlap constraints
Solution Approach 1:
The patent introduces a cache buffer as an intermediary between the host system and the SMR storage medium. This cache buffer temporarily stores write operations and manages the complexity of rewriting data in SMR storage by coordinating with the storage controller. The cache buffer absorbs the operational complexity of handling track overlap constraints and verification errors, simplifying the overall system operation while maintaining data correctness.
Data Source
AI summary
To provide enhanced operation of data storage devices and systems, various systems, apparatuses, methods, and software are provided herein. In a first example, a data storage device is presented with storage media comprising a cache storage region and a shingled magnetic recording (SMR) storage region that is divided into burst zones. A storage control system receives write operations and accumulates write data in the cache storage region until a commit threshold condition. Responsively, the storage control system transfers the write data into a burst zone of the SMR storage region, and verifies the write data written into the burst zone once the burst transfer is complete. Responsive to data verify errors in the write data written into the burst zone, the storage control system writes data associated with the data verify errors into an exception location associated with the burst zone.