Hi Li, Flink has disabled the RocksDb logs because sizing problems but you can have a look at this link [1] on how to enable them and setting the log directory. Let me know if that answers your question.
Best, Fabian [1] https://ververica.zendesk.com/hc/en-us/articles/360015933320-How-to-get-RocksDB-s-LOG-file-back-for-advanced-troubleshooting