Colin Patrick McCabe created HDFS-4953: ------------------------------------------
Summary: enable HDFS local reads via mmap Key: HDFS-4953 URL: https://issues.apache.org/jira/browse/HDFS-4953 Project: Hadoop HDFS Issue Type: New Feature Affects Versions: 2.2.0 Reporter: Colin Patrick McCabe Assignee: Colin Patrick McCabe Currently, the short-circuit local read pathway allows HDFS clients to access files directly without going through the DataNode. However, all of these reads involve a copy at the operating system level, since they rely on the read() / pread() / etc family of kernel interfaces. We would like to enable HDFS to read local files via mmap. This would enable truly zero-copy reads. In the initial implementation, zero-copy reads will only be performed when checksums were disabled. Later, we can use the DataNode's cache awareness to only perform zero-copy reads when we know that checksum has already been verified. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira