Hi I have deployed a Single node Alluxio cluster, and its working really fine and fast, but the problem I am facing is regarding Master node fails to start every time I restart my Alluxio machine. Receiving the below error:
2019-08-02 05:37:30,942 ERROR JournalStateMachine - Fatal error: Unexpected journal entry. The next expected SN is 0, but encountered an entry with SN 117719. Full journal entry: sequence_number: 117719
It looks like the journal (created by this master and needed to restart the master) is corrupted. Some journal entries (e.g., the first journal entry with seq num 0) are missing. Regarding the journal setting, you can refer to this documentation https://docs.alluxio.io/os/user/stable/en/operation/Journal.html
The most important configuration value to set for the journal is alluxio.master.journal.folder. This must be set to a filesystem folder that is available to all masters. In single-master mode, a local filesystem path may be used for simplicity.
Especially, check where do you set to save the journal and make sure do not delete files from the journal directory under "alluxio.master.journal.folder"