Write-ahead log (WAL) ensures crash recovery by logging changes before applying them
Image: Mike McMillan/USFS, Public domain, via Wikimedia Commons
Design of the FAT file system
Write-ahead log (WAL) ensures crash recovery by logging changes before applying them
The WAL mechanism records changes before they're applied to the file system. This preemptive logging helps in maintaining data integrity during unexpected crashes. By having a log of pending changes, the system can recover to a consistent state after a crash.
Example
If a crash occurs while writing to a file, the WAL records the intended changes. Upon recovery, the system can replay the logged changes to restore the file to its intended state.
This process is crucial for data integrity and system reliability, ensuring that no data is lost or corrupted during unexpected failures.
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