Shadow Volume for Block Storage Data Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Storage systems that export virtual disks to clients using block-based protocols are limited in their ability to manage data on a per lun basis, as they are unaware of the client file system and its data constructs, preventing the full exploitation of storage management capabilities.
Innovation Solution
A client-side agent interfaces with the client file system to determine the logical block layout and transmits this information to the storage system, allowing the storage system to create a shadow volume that can utilize file-level protocols and data management techniques, such as mirroring, to manage data containers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If storage systems export virtual disks using block-based protocols, then clients can access storage resources efficiently, but the storage system cannot manage data on a per-file basis and is unaware of client file system constructs
Solution Approach 1:
The patent implements a shadow volume that is nested within the exported virtual disk. The shadow volume is a file system structure created by the storage system that mirrors the client's file system layout, allowing the storage system to apply file-level management capabilities while the client continues to use block-based access. This nested structure enables dual-layer management: block-level for the client and file-level for the storage system.
Solution Approach 2:
The shadow volume acts as an intermediary layer between the block-based virtual disk and the storage system's file system management capabilities. It translates file-level operations from the storage system into block-level operations that the client can execute, enabling the storage system to manage data with file-level granularity without disrupting the client's block-based access model.
2Adaptability or versatility
If storage systems operate at block level only, then protocol compatibility is maintained, but file-level data management and protection techniques cannot be utilized
Solution Approach 1:
The patent segments the storage system into distinct functional layers: the block device layer that interfaces with clients using block-based protocols, and the shadow volume layer that provides file-level management capabilities. This segmentation allows each layer to operate independently with its own optimization, maintaining protocol compatibility at the block level while enabling file-level management at the shadow volume level.
Solution Approach 2:
The shadow volume provides multi-functionality by serving dual purposes: it acts as a container for file-level data management operations while simultaneously presenting a block device interface to clients. This universal structure enables the storage system to support both block-based and file-based access models through a single exported virtual disk.
3Ease of operation
If clients maintain file mappings and manage file semantics, then file access flexibility is improved, but the storage system cannot perform file-level data protection and management
Solution Approach 1:
The patent creates a shadow copy of the client's file system structure within the shadow volume. This copy includes file metadata, directory structures, and block mappings that mirror the client's file system state. The storage system uses this copied information to perform file-level operations such as snapshots, clones, and data protection without interfering with the client's file access flexibility.
Solution Approach 2:
The system implements feedback mechanisms where the client's file system operations are monitored and reported back to the storage system. The shadow volume maintains synchronization with the client's file system state, allowing the storage system to detect file-level changes and apply appropriate data protection measures based on the actual file system state observed through this feedback loop.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A system and method for examining the content of a client file system stored on an exported lun is provided. A client agent interfaces with a client file system to detemine block layout information of data containers within the client file system. This block layout information is then transmitted to the storage system exporting the lun. The storage system utilizes the block layout information to generate a shadow volume utilizing the storage system's file system.