Hi Suresh, HDFS-2006 adds new edit log ops (no modifications to existing ops) and a new XAttr INode Feature needs to be serialized to the fsimage. This required doing a NN layout version bump, so a 2.4 NN will not be able to start with these edit logs or images. Thus it's incompatible.
I think you're better equipped to comment on rolling upgrades, but based on my understanding, I think the above means we should still be able to rolling upgrade between 2.4 and whatever version eventually includes xattr support. RPC-wise, HDFS-2006 only adds new RPCs, so I don't think there are any concerns there. Thanks, Andrew On Fri, May 16, 2014 at 2:56 PM, Suresh Srinivas <sur...@hortonworks.com>wrote: > I have not looked at the development closely. With rolling upgrades > feature support in, are there any incompatible changes with this feature? > > Sent from phone > > > On May 16, 2014, at 10:30 AM, Chris Nauroth <cnaur...@hortonworks.com> > wrote: > > > > +1 for the merge. > > > > I've participated in ongoing design discussions and code reviews on > > individual patches. Yesterday, I completed a final review pass over the > > code in the feature branch, the design document, the end user > documentation > > and the test plan. It looks ready to me. > > > > Thank you to everyone who made contributions on the feature branch. > > > > Chris Nauroth > > Hortonworks > > http://hortonworks.com/ > > > > > > > > On Wed, May 14, 2014 at 9:20 AM, Andrew Wang <andrew.w...@cloudera.com > >wrote: > > > >> +1 from me as well, I've participated in review and development of this > >> branch and think it's ready for merge. > >> > >> Thanks, > >> Andrew > >> > >> > >> On Wed, May 14, 2014 at 5:47 AM, Gangumalla, Uma > >> <uma.ganguma...@intel.com>wrote: > >> > >>> 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>) > > > > -- > > CONFIDENTIALITY NOTICE > > NOTICE: This message is intended for the use of the individual or entity > to > > which it is addressed and may contain information that is confidential, > > privileged and exempt from disclosure under applicable law. If the reader > > of this message is not the intended recipient, you are hereby notified > that > > any printing, copying, dissemination, distribution, disclosure or > > forwarding of this communication is strictly prohibited. If you have > > received this communication in error, please contact the sender > immediately > > and delete it from your system. Thank You. > > -- > CONFIDENTIALITY NOTICE > NOTICE: This message is intended for the use of the individual or entity to > which it is addressed and may contain information that is confidential, > privileged and exempt from disclosure under applicable law. If the reader > of this message is not the intended recipient, you are hereby notified that > any printing, copying, dissemination, distribution, disclosure or > forwarding of this communication is strictly prohibited. If you have > received this communication in error, please contact the sender immediately > and delete it from your system. Thank You. >
