s3BackupMode

Defines how documents should be delivered to Amazon S3. When it is set to FailedDocumentsOnly, Firehose writes any documents that could not be indexed to the configured Amazon S3 destination, with AmazonOpenSearchService-failed/ appended to the key prefix. When set to AllDocuments, Firehose delivers all incoming records to Amazon S3, and also writes failed documents with AmazonOpenSearchService-failed/ appended to the prefix. For more information, see Amazon S3 Backup for the Amazon ES Destination. Default value is FailedDocumentsOnly.

You can't change this backup mode after you create the delivery stream.