Virtual Hot Spare RAID Rebuilder for Parallel Disk Reconstruction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In RAID data storage systems, the time required for hot spare disk rebuilds is prolonged due to the bottleneck of single I/O interfaces, especially with lower-cost SATA drives, leading to increased vulnerability during the rebuild process and potential data loss from secondary disk failures.
Innovation Solution
Implementing virtual hot spares distributed across multiple physical disk drives in a separate RAID group to spread data write operations, reducing rebuild time and enhancing fault tolerance by allocating storage capacity on-the-fly to match failed disk capacities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single hot spare disk is used for RAID reconstruction, then the system provides fault tolerance, but the rebuild time is prolonged due to single I/O interface bottleneck
Solution Approach 1:
The patent divides the hot spare reconstruction process into multiple parallel segments by distributing the reconstruction across multiple I/O interfaces. Instead of using a single hot spare disk with one I/O interface, the system creates multiple virtual hot spare disks, each handled by separate I/O interfaces, allowing simultaneous reconstruction operations that reduce overall rebuild time while maintaining fault tolerance.
2Ease of manufacture
If lower-cost SATA drives are used, then the system reduces cost, but the rebuild time increases due to slower I/O interface
Solution Approach 1:
The patent introduces a virtual dimension to the hot spare architecture by creating virtual hot spare disks that map to physical disks across different RAID groups. This virtual layer allows the system to distribute reconstruction operations across multiple physical I/O interfaces simultaneously, effectively compensating for the slower speed of lower-cost SATA drives and reducing overall rebuild time without increasing hardware cost.
3Reliability
If a dedicated hot spare disk is allocated per RAID group, then the system provides immediate redundancy, but the device complexity increases
Solution Approach 1:
The patent makes the hot spare mechanism universal by allowing any disk in any RAID group to serve as a virtual hot spare for another RAID group. Instead of requiring dedicated hot spare disks for each RAID group, the system creates a pool of virtual hot spares where disks can be dynamically assigned based on failure conditions, reducing overall system complexity while maintaining redundancy capabilities.
4Device complexity
If the hot spare is rebuilt using single I/O interface, then the system maintains simplicity, but the vulnerability to secondary failures increases during rebuild
Solution Approach 1:
The patent performs preliminary actions by pre-creating virtual hot spare mappings and preparing multiple I/O interfaces for concurrent reconstruction operations. When a disk failure occurs, the system already has pre-configured virtual hot spare paths ready, allowing immediate multi-interface reconstruction without waiting for sequential setup, thus reducing vulnerability to secondary failures while maintaining operational simplicity.
Data Source
AI summary
A data volume rebuilder reduces the time required to reconstruct lost data in a RAID protected data volume operating with a failed physical disk drive. A data volume rebuilder uses the remaining functioning physical disk drives in the RAID protected data volume operating with the failed disk to regenerate the lost data and populate a virtual hot spare store allocated in a separate RAID protected data volume. The recovered data is distributed across the physical disk drives supporting the virtual hot spare store. Once the virtual hot spare store is populated, the data volume can recover from a subsequent failure of a second physical disk drive in either RAID group. After replacement of the failed physical disk drive, the data volume rebuilder moves the recovered data from the virtual hot spare store to the new physical disk drive.