It happens when we are not in partial log aggregation.
When we are not in partial log aggregation, we will not create intermediate checksum file, so, when we do postWrite, we would call
deleteFileWithRetries(fc, ugi, remoteLogCheckSumFile);
which will throw out exception, and complain that the remoteLogCheckSumFile can not be found. So, we would mark the log aggregation status as Failed when we catch the exception.