臺灣博碩士論文加值系統

System failure always happens due to power outage, there would lost many data if power outage occurs. Even there have some methods like UPS to prevent data loss, but it costs too high. We proposed a technique based on battery-backed memory to protect file systems from losing data across power failures and guaranteed file system integrity.
The idea is simple: when power restores after a power outage, our method salvages modified but unwritten data by scanning and parsing the contents in memory.
We have implement our method on Ext3 file system and improve recovery ability compared to the ordinary file system recovery. Besides, our approach is also beneficial to integrity-aware applications like databases.

System failure always happens due to power outage, there would lost many data if power outage occurs. Even there have some methods like UPS to prevent data loss, but it costs too high. We proposed a technique based on battery-backed memory to protect file systems from losing data across power failures and guaranteed file system integrity.
The idea is simple: when power restores after a power outage, our method salvages modified but unwritten data by scanning and parsing the contents in memory.
We have implement our method on Ext3 file system and improve recovery ability compared to the ordinary file system recovery. Besides, our approach is also beneficial to integrity-aware applications like databases.

Table of Contents iii
List of Tables iv
List of Figures v
Abstract vi
Acknowledgements vii
1 Introduction 1
2 Related Work 4
3 Design Concept 6
3.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.2 Checkpoint-Based Data Recovery . . . . . . . . . . . . . . . . . . . . . . . 7
3.3 File-Operation-Based Data Recovery . . . . . . . . . . . . . . . . . . . . . 9
3.4 Implementation for Ext3 File System . . . . . . . . . . . . . . . . . . . . . 11
3.4.1 The Recovery Procedure in the Boot Loader . . . . . . . . . . . . 11
3.4.2 Checkpointing with Ext3 Transactions . . . . . . . . . . . . . . . 12
3.4.3 Managing Atomic Sets using Ext3 Handles . . . . . . . . . . . . . 14
4 Experimental Results 17
4.1 Experimental Setup and Performance Metrics . . . . . . . . . . . . . . . . 17
4.2 Data Recovery Capability . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.2.1 Data loss comparison: Prompt Return . . . . . . . . . . . . . . . . 19
4.2.2 Data loss comparison: Worst-case Scenario . . . . . . . . . . . . . . 19
4.3 MySQL+Sysbench . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5 Conclusion 24
Bibliography 25

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