data_engine probe periodically stops and in data_engine.log I see
ADO_Database::ExecuteSP com error for [Microsoft OLE DB Provider for SQL Server] The transaction log for database 'CA_UIM' is full due to 'ACTIVE_BACKUP_OR_RESTORE'.
Cause
SQL has run out of space for transaction log and therefore the data_engine cannot write any data to db.
Environment
Release: Component: UIMDEG
Resolution
Provide more space either by increasing size of transaction log or by truncating it.
Should also check that autogrow is not at default of 1MB for data files and 10% for transaction log, Increase both to a fixed MB value (e.g. 100MB) to ensure that the DB can always keep up with demand