Storage Control System Partial Device Error Recovery
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Solution Overview
Problem
Conventional data storage systems face inefficiencies in recovering from partial device errors, as identifying lost data items in corrupted regions requires scanning entire metadata, leading to slow, expensive, and resource-intensive processes, often resulting in full device rebuilds.
Innovation Solution
The system partitions storage capacity into segments, groups them into segment groups, generates parity data, and persistently stores it to enable recovery from partial device errors by using parity data segments and non-corrupted segments without performing a full device rebuild.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the storage control system scans the entire metadata to identify lost data items in a corrupted region, then it can accurately identify all lost data, but the recovery process becomes prohibitively slow, expansive, and resource intensive
Solution Approach 1:
The patent divides the storage device into multiple segments and groups them into segment groups, where each segment group has an associated parity data segment. This segmentation allows the system to identify lost data by examining only the specific segment group containing the corruption rather than scanning the entire metadata, thereby maintaining identification accuracy while dramatically reducing recovery time and resource consumption.
2Reliability
If the storage control system performs a full device rebuild to fix local partial errors, then it can ensure complete data recovery, but the process becomes resource intensive and time consuming
Solution Approach 1:
The patent implements segmentation of the storage device into segments organized in segment groups, with each group having its own parity data segment. This allows the system to perform localized recovery operations on only the affected segment group rather than rebuilding the entire device, ensuring complete recovery of lost data while maintaining high system availability and reducing resource consumption.
Solution Approach 2:
The patent changes the scope of the recovery operation from a full device rebuild to a localized segment group recovery. By modifying the parameter of recovery scope and using the associated parity data segment, the system achieves complete data recovery for the corrupted region while dramatically improving productivity and system availability.
3Reliability
If the storage control system uses conventional data replication techniques, then it can protect against complete storage node failure, but it cannot efficiently handle partial device errors without full device rebuilds
Solution Approach 1:
The patent extends conventional data replication by dividing the storage device into segments organized in segment groups, with each group having its own parity data segment. This segmentation enables the system to efficiently handle partial device errors by performing localized recovery on the affected segment group using its associated parity data, rather than requiring complex full device rebuilds, thereby maintaining reliability while simplifying the recovery process.
Data Source
AI summary
Techniques are provided to recover from partial device errors of storage devices in a data storage system. A storage control system manages a storage device which comprises storage capacity that is logically partitioned into segments of equal size. The storage control system groups at least some of the segments of the storage device into a segment group. Each segment of the segment group is configured to store one or more data items and associated metadata items. The storage control system generates a parity data segment based on the segments of the segment group, and persistently stores the parity data segment in association with the segment group. In response to detecting a storage device error associated with a corrupted segment of the segment group, the storage control system utilizes the parity data segment and non-corrupted segments of the segment group to recover at least one missing data item of the corrupted segment.