The fourth hbase 0.90.0 release candidate is available for download: http://people.apache.org/~stack/hbase-0.90.0-candidate-3/
This is going to be the one! Should we release this candidate as hbase 0.90.0? Take it for a spin. Check out the doc., etc. Vote +1/-1 by next Friday, the 14th of January. HBase 0.90.0 is the major HBase release that follows 0.20.0 and the fruit of the 0.89.x development release series we've been running of late. Over 1k issues have been closed since 0.20.0. Release notes are available here: http://su.pr/8LbgvK. HBase 0.90.0 runs on Hadoop 0.20.x. It does not currently run on Hadoop 0.21.0 nor on Hadoop TRUNK. HBase will lose data unless it is running on an Hadoop HDFS 0.20.x that has a durable sync. Currently only the branch-0.20-append branch [1] has this attribute (See CHANGES.txt [3] in branch-0.20-append to see the list of patches involved adding an append). No official releases have been made from this branch as yet so you will have to build your own Hadoop from the tip of this branch, OR install Cloudera's CDH3 [2] (Its currently in beta). CDH3b2 or CDHb3 have the 0.20-append patches needed to add a durable sync. If using CDH, be sure to replace the hadoop jars that are bundled with HBase with those from your CDH distribution. There is no migration necessary. Your data written with HBase 0.20.x (or with HBase 0.89.x) is readable by HBase 0.90.0. A shutdown and restart after putting in place the new HBase should be all thats involved. That said, once done, there is no going back to 0.20.x once the transition has been made. HBase 0.90.0 and HBase 0.89.x write region names differently in the filesystem. Rolling restart from 0.20.x or 0.89.x to 0.90.0RC1 will not work. Yours, The HBasistas P.S. For why the version 0.90 and whats new in HBase 0.90, see slides 4-10 in this deck [4] 1. http://svn.apache.org/viewvc/hadoop/common/branches/branch-0.20-append 2. http://archive.cloudera.com/docs/ 3. http://svn.apache.org/viewvc/hadoop/common/branches/branch-0.20-append/CHANGES.txt 4. http://hbaseblog.com/2010/07/04/hug11-hbase-0-90-preview-wrap-up/
