# Commit Logs
+ Once logs are replicated to quorum peers, they are considered committed
+ Committed logs are safe to apply operation to application data
+ Only uncommitted logs can be overwritten
  + The overwrite happens when `leader` changes
  + `Leader` requires quorum votes
  + Committed logs requires quorum acknowledgement
+ New `leader` may have uncommitted logs from old `leader`
+ Question: How to commit logs safely?
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