Data Extent Reordering for Secure Tape Storage
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Solution Overview
Problem
Existing access control methods, such as encryption, are inefficient for managing different expiration dates and are not suitable for media with slow write speeds like magnetic tape, as complete erasure is required to prevent data recovery.
Innovation Solution
A method involving splitting a file into sequential extents, reordering them non-sequentially, writing dummy data, and recording extent placement information to control access, allowing for fine-grained expiration dates without full erasure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If encryption is used for access control, then data security is improved, but key management complexity increases and expiration control becomes inefficient
Solution Approach 1:
The patent divides data into multiple extents and stores them separately on the storage medium. Each extent can be independently controlled and expired, eliminating the need for encryption keys and simplifying access control management while maintaining data security through physical separation and controlled access.
2Reliability
If complete erasure is performed to prevent data recovery on slow write media, then data security is improved, but write time and productivity decrease
Solution Approach 1:
The patent extracts the security control mechanism from the data itself and implements it at the extent level through separate storage locations and access control metadata. This allows selective expiration of individual extents without requiring complete media erasure, enabling efficient security control on slow write media like magnetic tape.
3Productivity
If data is stored in sequential order, then write efficiency is improved, but access control and expiration management become difficult
Solution Approach 1:
The patent applies different storage characteristics to different parts of the data by dividing it into extents with unique identifiers and storing them at different locations on the medium. Each extent can have independent access control and expiration settings, providing fine-grained control while maintaining efficient sequential writing through the use of extent maps for retrieval.
Data Source
AI summary
A method, executed by a computer, for recording data includes splitting a file into sequential extents, reordering the sequential extents into non-sequential extents, writing the non-sequential extents to a storage medium, writing dummy data to the storage medium, and writing extent placement information corresponding to a placement for the non-sequential extents to the storage medium. A computer program product and computer system corresponding to the above method are also disclosed herein.