If a record fails during a crawl, the IAS Server discards the failed record and writes a truncated version of the record to the ias-service.log file. If you do not want the IAS Server to write any information about failed records to the log file, you can disable logging for failed records by un-commenting a setting in the ias-service-log4j.properties file.
To exclude failed records from the IAS Service log file:
Once you un-comment the setting, the IAS Server does not write any information about failed records to the log file. However, failed records are still counted as metrics under FAILED_RECORDS.