On Aug 31, 2011, at 11:41 AM, sanjay Radia wrote: > > I propose that the 20-append patches (details below) be included in 20.205 > which will become the first official Apache > release of Hadoop that supports Append and HBase. >
> Background: > There hasn't been a official Apache release that supports HBase. > The HBase community have instead been using the 20-append branch; the patches > were contributed by the HBase community including Facebook. The Cloudera > distribution has also included these patches. > Andrew Purtell has ported these patches to 20-security branch. > +1 I think it's high time (I thought so too last Dec too: http://s.apache.org/jr) we had an official Hadoop release which supports HBase. Thanks for all the effort Andrew - it will be really nice to have an Apache 0.20 with security+append! Arun > Risk Level: > These patches have been used and tested on large HBase clusters by FB , by > those who use 20-append branch directly (various users including a 500 node > HBase cluster at Yahoo) and by those that use the Cloudera distribution. We > have reviewed the patches and have conducted further tests; testing and > validation continues. > > > Patches: > HDFS-200. Support append and sync for hadoop 0.20 branch. > HDFS-142. Blocks that are being written by a client are stored in the > blocksBeingWritten directory. > HDFS-1057. Concurrent readers hit ChecksumExceptions if following a writer > to very end of file > HDFS-724. Use a bidirectional heartbeat to detect stuck pipeline. > HDFS-895. Allow hflush/sync to occur in parallel with new writes to the file. > HDFS-1520. Lightweight NameNode operation recoverLease to trigger lease > recovery. > HDFS-1555. Disallow pipelien recovery if a file is already being lease > recovered. > HDFS-1554. New semantics for recoverLease. > HDFS-988. Fix bug where savenameSpace can corrupt edits log. > HDFS-826. Allow a mechanism for an application to detect that datanode(s) > have died in the write pipeline. > HDFS-630. Client can exclude specific nodes in the write pipeline. > HDFS-1141. completeFile does not check lease ownership. > HDFS-1204. Lease expiration should recover single files, not entire lease > holder > HDFS-1254. Support append/sync via the default configuration. > HDFS-1346. DFSClient receives out of order packet ack. > HDFS-1054. remove sleep before retry for allocating a block. >
