Hello HDFS Devs, I would like to call for a vote to merge the HDFS Extended Attributes (XAttrs) feature from the HDFS-2006 branch to the trunk. XAttrs are already widely supported on many operating systems, including Linux, Windows, and Mac OS. This will allow storing attributes for HDFS file/directory. XAttr consist of a name and a value and exist in one of 4 namespaces: user, trusted, security, and system. An XAttr name is prefixed with one of these namespaces, so for example, "user.myxattr". Consistent with ongoing awareness of Namenode memory usage, the maximum number and size of XAttrs on a file/directory are limited by a configuration parameter. The design document contains more details and can be found here: https://issues.apache.org/jira/secure/attachment/12644341/HDFS-XAttrs-Design-3.pdf Development of this feature has been tracked in JIRA HDFS-2006: https://issues.apache.org/jira/browse/HDFS-2006 All of the development work for the feature is contained in the "HDFS-2006" branch: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-2006 As last tasks, we are working to support XAttrs via libhdfs, webhdfs as well as other minor improvements. We intend to finish those enhancements before the vote completes and otherwise we could move them to top-level JIRAs as they can be tracked independently. User document is also ready for this feature. Here the doc attached in JIRA: https://issues.apache.org/jira/secure/attachment/12644787/ExtendedAttributes.html The XAttrs feature is backwards-compatible and enabled by default. A cluster administrator can disable it. Testing: We've developed more than 70 new tests which cover the XAttrs get, set and remove APIs through DistributedFileSystem and WebHdfsFileSystem, the new XAttr CLI commands, HA, XAttr persistence in the fsimage and related. Additional testing plans are documented in: https://issues.apache.org/jira/secure/attachment/12644342/Test-Plan-for-Extended-Attributes-1.pdf Thanks a lot to the contributors who have helped and participated in the branch development. Code contributors are Yi Liu, Charles Lamb, Andrew Wang and Uma Maheswara Rao G. The design document incorporates feedback from many community members: Chris Nauroth, Andrew Purtell, Tianyou Li, Avik Dey, Charles Lamb, Alejandro, Andrew Wang, Tsz Wo Nicholas Sze and Uma Maheswara Rao G. Code reviewers on individual patches include Chris Nauroth, Alejandro, Andrew Wang, Charles Lamb, Tsz Wo Nicholas Sze and Uma Maheswara Rao G.
Also thanks to Dhruba for bringing up this JIRA and thanks to others who participated for discussions. This vote will run for a week and close on 5/21/2014 at 06:16 pm IST. Here is my +1 to start with. Regards, Uma (umamah...@apache.org<mailto:umamah...@apache.org>)
