[ https://issues.apache.org/jira/browse/HDFS-7291?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Chris Nauroth updated HDFS-7291: -------------------------------- Resolution: Fixed Fix Version/s: 2.6.0 Status: Resolved (was: Patch Available) I committed this to trunk, branch-2 and branch-2.6. Xiaoyu, thank you for contributing the patch. Haohui, Allen and Colin, thank you for code reviews. > Persist in-memory replicas with appropriate unbuffered copy API on POSIX and > Windows > ------------------------------------------------------------------------------------ > > Key: HDFS-7291 > URL: https://issues.apache.org/jira/browse/HDFS-7291 > Project: Hadoop HDFS > Issue Type: Sub-task > Components: datanode > Affects Versions: 2.6.0 > Reporter: Xiaoyu Yao > Assignee: Xiaoyu Yao > Fix For: 2.6.0 > > Attachments: HDFS-7291.0.patch, HDFS-7291.1.patch, HDFS-7291.2.patch, > HDFS-7291.3.patch, HDFS-7291.4.patch > > > HDFS-7090 changes to persist in-memory replicas using unbuffered IO on Linux > and Windows. On Linux distribution, it relies on the sendfile() API between > two file descriptors to achieve unbuffered IO copy. According to Linux > document at http://man7.org/linux/man-pages/man2/sendfile.2.html, this is > only supported on Linux kernel 2.6.33+. > As pointed by Haowei in the discussion below, FileChannel#transferTo already > has support for native unbuffered IO on POSIX platform. On Windows, JDK 6/7/8 > has not implemented native unbuffered IO yet. We change to use > FileChannel#transfer for POSIX and our own native wrapper of CopyFileEx on > Windows for unbuffered copy. -- This message was sent by Atlassian JIRA (v6.3.4#6332)