When I use Amazon Elastic MapReduce (Amazon EMR) to transform or move data into or out of Amazon S3, several empty files with the "<directoryname>_$folder$" suffix appear in my S3 buckets. What are these files, and is it safe to delete them?

Amazon EMR is a web service that uses a managed Hadoop framework to process, distribute, and interact with data in AWS data stores, including Amazon S3. Because S3 uses a key-value pair storage system, the Hadoop file system implements directory support in S3 by creating empty files with the "<directoryname>_$folder$" suffix.

You can safely delete any empty files with the '<directoryname>_$folder$" suffix that appear in your S3 buckets. These empty files are created by the Hadoop framework at runtime, but Hadoop is designed to process data even if these empty files are removed.

Amazon EMR, EMR_FS, S3N, Hadoop File System, _$folder$, S3, key-value pair


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Published: 2016-04-29