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Date: Tue, 7 Dec 2010 09:25:26 -0800
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Subject: ANN: The second hbase 0.90.0 release candidate is available for
 download
From: Stack <stack@duboce.net>
To: HBase Dev List <dev@hbase.apache.org>
Content-Type: text/plain; charset=ISO-8859-1

The second hbase 0.90.0 release candidate is available for download:

 http://people.apache.org/~stack/hbase-0.90.0-candidate-1/

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.

More than 974 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.

Should we release this candidate as hbase 0.90.0?  Take it for a spin.
 Check out the doc., etc.  Vote +1/-1 by December 13th.

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/