Shared Storage Snapshot Mapping Table
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Solution Overview
Problem
Existing snapshot data processing methods are inefficient due to the need for multiple copy-on-write and mapping entry insertions for each snapshot of a production volume, leading to increased resource usage and reduced efficiency.
Innovation Solution
A shared storage device uses a mapping table to store copy-on-write data and mapping entry information, allowing all activated snapshots of a production volume to share the same copy of copy-on-write data and corresponding mapping entry information, reducing the number of copy-on-write operations and improving efficiency by storing only data differences between snapshot time points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copy-on-write and mapping entry insertion are performed for each snapshot of a production volume, then data protection and snapshot functionality are achieved, but processing efficiency deteriorates due to multiple redundant operations on the same data
Solution Approach 1:
The patent merges the copy-on-write data storage across multiple snapshots by introducing a shared storage device. When the same data needs to be copied for multiple snapshots, instead of creating separate copies in each snapshot's storage, the system stores a single copy in the shared storage device and establishes mapping relationships from multiple snapshots to this single copy. This merging approach eliminates redundant storage and reduces the number of copy-on-write operations, directly resolving the contradiction between maintaining data protection reliability and improving processing efficiency.
2Stability of the object's composition
If multiple copy-on-write operations are performed for multiple snapshots on the same logical unit data, then each snapshot maintains data consistency, but resource usage increases and processing time is extended
Solution Approach 1:
The patent implements preliminary action by pre-establishing the shared storage structure and mapping table before snapshots are created. The system proactively sets up the shared storage device and the mapping relationships between logical units and storage locations. When snapshots are subsequently created, the system only needs to update the mapping table to point to the pre-prepared shared storage locations, rather than performing full copy-on-write operations at snapshot creation time. This preliminary preparation significantly reduces the time required for snapshot operations while maintaining data consistency.
3Reliability
If separate copy-on-write data is stored for each snapshot, then snapshot independence is ensured, but storage space consumption increases
Solution Approach 1:
The patent applies universality by making the shared storage device serve multiple snapshots simultaneously. A single storage location in the shared storage device can be referenced by multiple snapshots through the mapping table, allowing the same physical storage resources to fulfill the data protection requirements of multiple snapshots. This multi-functional use of storage space dramatically reduces the total quantity of storage resources needed while ensuring that each snapshot maintains its independence and data consistency through unique mapping relationships.
Data Source
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AI summary
Embodiments of the present invention disclose a data processing method and apparatus, and a shared storage device, where the method includes: receiving, by a shared storage device, a copy-on-write request sent by another storage device, where the copy-on-write request includes data on which copy-on-write is to be performed and a logical unit identifier and snapshot time point of the data; storing the data; and searching, according to the logical unit identifier and snapshot time point of the data, a preset shared mapping table for a corresponding entry, and storing, in the corresponding entry, mapping entry information of the data, where the mapping entry information includes the logical unit identifier and snapshot time point of the data and a storage address that is of the data and in the shared storage device, which can improve efficiency of snapshot data processing.