Deduplicated Tape Backup Catalog for Restore Performance
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Solution Overview
Problem
The inefficiency of restoring deduplicated data from tape storage devices due to the need for repeated tape swapping, which increases the time and cost of accessing data, while also losing the space reduction benefits of deduplication during the rehydration process.
Innovation Solution
A method that involves sorting and writing deduplicated backup images to tape in a sequential order, using fingerprint values to identify storage locations, and creating a map for efficient restoration, allowing for concurrent access and reducing the need for tape swapping during the restore process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If deduplicated data is stored across multiple tapes, then storage space efficiency is improved, but restore performance deteriorates due to repeated tape swapping
Solution Approach 1:
The system performs preliminary actions during the backup phase by organizing deduplicated data blocks with their metadata (fingerprint, tape location, offset) in a structured catalog. This pre-organization enables efficient restore operations without requiring tape swapping, as the system can directly navigate to the required data blocks on the mounted tape.
Solution Approach 2:
The backup image is segmented into multiple data blocks that are distributed across tapes based on their deduplication fingerprints. Each block is independently addressable through the catalog, allowing the system to retrieve only the necessary segments during restore operations without needing to swap tapes.
2Loss of energy
If tape storage devices are used for long-term data storage, then cost and energy consumption are reduced, but access time increases due to sequential access nature
Solution Approach 1:
The system creates a detailed catalog during backup that maps each data block's fingerprint to its physical location on tape (tape ID, block number, offset). This preliminary indexing structure allows the system to mount a single tape and directly access any required data block without sequential scanning, dramatically reducing access time while maintaining the energy efficiency of tape storage for archival purposes.
3Quantity of substance
If multiple tapes are used for storing backup images, then storage capacity is increased, but the complexity of tape management and swapping increases
Solution Approach 1:
The system introduces a catalog data structure as an intermediary between the physical tape storage and the restore operations. The catalog contains fingerprint-to-location mappings that enable the system to manage multiple tapes efficiently by translating logical data block requests into physical tape locations, eliminating the need for complex manual tape swapping and management.
4Quantity of substance
If deduplicated data is restored from tape storage, then storage space benefits are lost during rehydration, but data accessibility is improved
Solution Approach 1:
The system performs preliminary organization of deduplicated data blocks with complete location metadata during the backup phase. This pre-structuring enables direct access to deduplicated blocks during restore operations without requiring full rehydration to intermediate storage, allowing the system to maintain storage space efficiency while improving data accessibility through direct tape-to-destination restoration.
Data Source
AI summary
Various systems and methods can be used to perform backup to tape. For example, one method involves detecting an amount of storage in a tape drive that is available for concurrent access. The method then compares the size of a plurality of backup images to the amount of storage prior to initiating an archive operation. The method then involves adding information identifying a backup image to a list of backup images to be included in an archive operation and performing the archive operation, which involves writing the backup images to tape drive.