Log structured (or journaling) file systems record each metadata update to the file system as a transaction
All transactions are written to a log
A transaction is considered committed once it is written to the log (sequentially)
Sometimes to a separate device or section of disk
However, the file system may not yet be updated
The transactions in the log are asynchronously written to the file system structures
When the file system structures are modified, the transaction is removed from the log
If the file system crashes, all remaining transactions in the log must still be performed
Faster recovery from crash, removes chance of inconsistency of metadata