RAID Rebuilding via Disk Balance Process
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Solution Overview
Problem
In storage processing, when a storage drive fails in a RAID array and no spare drive is available, the rebuilding process is delayed, increasing the risk of permanent data loss due to the array being placed in an exposed state.
Innovation Solution
Identify a source storage drive involved in a disk balance process and leverage it to initiate the rebuilding of the RAID array by reconstructing data on that drive, allowing the rebuilding process to proceed simultaneously with the disk balance task, thus avoiding the need for a spare drive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spare storage drive is used to replace the failed drive in a RAID array, then the rebuilding process can proceed immediately, but the system requires availability of spare drives which may not always be available
Solution Approach 1:
The patent makes an active storage drive serve dual purposes: continuing its normal storage function while simultaneously serving as a temporary target for rebuilding data from the failed drive. This multi-functionality eliminates the need for dedicated spare drives, as any active drive can be temporarily repurposed for the rebuilding process.
Solution Approach 2:
The patent introduces a temporary copying mechanism that acts as an intermediary between the failed drive and the eventual replacement. Data is first copied to a temporary location on an active drive, then the failed drive is replaced, and finally the data is migrated to the new drive. This intermediary approach enables rebuilding to proceed without requiring pre-available spare drives.
2Reliability
If the rebuilding process waits for a spare drive to become available, then system stability is maintained, but the rebuilding process is delayed increasing the risk of permanent data loss
Solution Approach 1:
The patent performs preliminary copying of data from the failed drive to an active drive before the actual drive replacement occurs. This preliminary action ensures that data is secured and the rebuilding process can commence immediately after replacement, eliminating waiting time while maintaining data safety through the preliminary copy operation.
Solution Approach 2:
The patent enables the rebuilding process to continue without interruption by using an active drive as a temporary target. Instead of pausing to wait for spare drive availability, the system maintains continuous useful action by immediately initiating the rebuild process using available resources, thereby eliminating delays and reducing the window of vulnerability.
3Productivity
If data is reconstructed on an active drive during normal operation, then rebuilding can proceed without spare drives, but the active drive must handle both normal I/O and rebuilding operations simultaneously
Solution Approach 1:
The patent segments the drive operations by separating normal I/O operations from rebuilding operations. The active drive is divided into functional segments: one handling normal storage operations and another dedicated to receiving rebuilt data. This segmentation allows both operations to proceed simultaneously with minimal interference, managing complexity through functional separation.
Data Source
AI summary
Solutions for processing a redundant array of storage drives receiving a rebuilding request of a redundant array of storage drives. The redundant array has a first storage drive to be replaced. In response to no spare storage drive being available to logically replace the first storage drive, a second storage drive is identified, which is a source storage drive of a disk balance process being performed. A rebuilding of the redundant array is initiated by reconstructing data of the first storage drive on the second storage drive during the disk balance process.