Read Request Chaining for Mirrored File System Verification
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Solution Overview
Problem
Current RAID systems experience delays in verifying data integrity between source and destination volumes due to inefficient read operations across multiple disks during mirroring, as striping is optimized for writes but not for reads.
Innovation Solution
The method chains read request blocks to a single disk, eliminating the need for read striping across multiple disks, allowing for concurrent transmission and reducing the time required to verify data integrity by enabling faster read operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If read striping is performed across multiple disks during verification, then data can be read from all disks in parallel, but the read operation cannot complete until reads are finished across all disks, causing delays
Solution Approach 1:
The patent segments the verification process into independent per-disk operations. Instead of requiring all disks to complete reads simultaneously, each disk's read operations are processed independently and sequentially verified. This allows the system to avoid the bottleneck of waiting for all striped reads to complete while still achieving comprehensive verification.
2Productivity
If striping is used for writes across multiple disks, then write performance is optimized, but read operations are not optimized and require waiting for all disks
Solution Approach 1:
The patent inverts the traditional striped read approach by processing reads disk-by-disk in sequence rather than requiring simultaneous completion from all disks. This inversion allows write-optimized striping to remain intact while simplifying read operations, as each disk can be verified independently without coordinating across the entire stripe set.
3Reliability
If reads are performed across all multiple disks before obtaining read data, then data integrity can be verified, but there is a delay in verifying if destination volume data is identical to source volume data
Solution Approach 1:
The patent performs preliminary verification actions on each disk independently as reads complete, rather than waiting for all reads to finish. This allows the system to begin integrity checking and comparison operations early on individual disks while other disks are still being read, significantly reducing total verification time while maintaining comprehensive data integrity checking.
Data Source
AI summary
An embodiment of the invention provides an apparatus and method for optimizing reads in a mirrored file system. The apparatus and method receives a plurality of read request blocks for reading the target regions in disks. The apparatus and method will chain the read request blocks in a first set, where all of the read request blocks in the first set are targeted to a first disk. The read request blocks in the first set are then sent as a read request to the first disk. When each read request block in the first set has completed accessing their respective target regions in the first disk, then the read data is generated from the first disk. Therefore, by chaining the read request blocks in a read request to a single disk, read striping is not performed across multiple disks during a read operation.