Repository: hbase Updated Branches: refs/heads/master 9f8d1876a -> 257ab6525
HBASE-11459 Add more doc on compression codecs, how to hook up native lib, lz4, etc. Project: http://git-wip-us.apache.org/repos/asf/hbase/repo Commit: http://git-wip-us.apache.org/repos/asf/hbase/commit/257ab652 Tree: http://git-wip-us.apache.org/repos/asf/hbase/tree/257ab652 Diff: http://git-wip-us.apache.org/repos/asf/hbase/diff/257ab652 Branch: refs/heads/master Commit: 257ab6525efc3575adaf7f4ef69d52a9bca7d1ec Parents: 9f8d187 Author: stack <[email protected]> Authored: Wed Jul 2 16:42:32 2014 -0700 Committer: stack <[email protected]> Committed: Wed Jul 2 16:44:50 2014 -0700 ---------------------------------------------------------------------- src/main/docbkx/book.xml | 86 +++++++++++++++++++++++++++++++++---------- 1 file changed, 67 insertions(+), 19 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/hbase/blob/257ab652/src/main/docbkx/book.xml ---------------------------------------------------------------------- diff --git a/src/main/docbkx/book.xml b/src/main/docbkx/book.xml index 6c4c9ef..a5e3517 100644 --- a/src/main/docbkx/book.xml +++ b/src/main/docbkx/book.xml @@ -4330,7 +4330,20 @@ This option should not normally be used, and it is not in <code>-fixAll</code>. <appendix xml:id="compression"> <title >Compression In HBase<indexterm><primary>Compression</primary></indexterm></title> - <para>There are a bunch of compression options in HBase. There is some helpful discussion + <para>There are a bunch of compression options in HBase. Some codecs come with java -- + e.g. gzip -- and so require no additional installations. Others require native + libraries. The native libraries may be available in your hadoop as is the case + with lz4 and it is just a matter of making sure the hadoop native .so is available + to HBase. You may have to do extra work to make the codec accessible; for example, + if the codec has an apache-incompatible license that makes it so hadoop cannot bundle + the library.</para> + <para>Below we + discuss what is necessary for the common codecs. Whatever codec you use, be sure + to test it is installed properly and is available on all nodes that make up your cluster. + Add any necessary operational step that will ensure checking the codec present when you + happen to add new nodes to your cluster. The <xref linkend="compression.test" /> + discussed below can help check the codec is properly install.</para> + <para>As to which codec to use, there is some helpful discussion to be found in <link xlink:href="http://search-hadoop.com/m/lL12B1PFVhp1";>Documenting Guidance on compression and codecs</link>. </para> @@ -4341,11 +4354,25 @@ This option should not normally be used, and it is not in <code>-fixAll</code>. To run it, type <code>/bin/hbase org.apache.hadoop.hbase.util.CompressionTest</code>. This will emit usage on how to run the tool. </para> - <note><title>You need to restart regionserver for it to pick up fixed codecs!</title> + <note><title>You need to restart regionserver for it to pick up changes!</title> <para>Be aware that the regionserver caches the result of the compression check it runs - ahead of each region open. This means - that you will have to restart the regionserver for it to notice that you have fixed - any codec issues.</para> + ahead of each region open. This means that you will have to restart the regionserver + for it to notice that you have fixed any codec issues; e.g. changed symlinks or + moved lib locations under HBase.</para> + </note> + <note xml:id="hbase.native.platform"><title>On the location of native libraries</title> + <para>Hadoop looks in <filename>lib/native</filename> for .so files. HBase looks in + <filename>lib/native/PLATFORM</filename>. See the <command>bin/hbase</command>. + View the file and look for <varname>native</varname>. See how we + do the work to find out what platform we are running on running a little java program + <classname>org.apache.hadoop.util.PlatformName</classname> to figure it out. + We'll then add <filename>./lib/native/PLATFORM</filename> to the + <varname>LD_LIBRARY_PATH</varname> environment for when the JVM starts. + The JVM will look in here (as well as in any other dirs specified on LD_LIBRARY_PATH) + for codec native libs. If you are unable to figure your 'platform', do: + <programlisting>$ ./bin/hbase org.apache.hadoop.util.PlatformName</programlisting>. + An example platform would be <varname>Linux-amd64-64</varname>. + </para> </note> </section> @@ -4376,6 +4403,41 @@ This option should not normally be used, and it is not in <code>-fixAll</code>. </para> </section> + <section xml:id="gzip.compression"> + <title> + GZIP + </title> + <para> + GZIP will generally compress better than LZO but it will run slower. + For some setups, better compression may be preferred ('cold' data). + Java will use java's GZIP unless the native Hadoop libs are + available on the CLASSPATH; in this case it will use native + compressors instead (If the native libs are NOT present, + you will see lots of <emphasis>Got brand-new compressor</emphasis> + reports in your logs; see <xref linkend="brand.new.compressor" />). + </para> + </section> + + <section xml:id="lz4.compression"> + <title> + LZ4 + </title> + <para> + LZ4 is bundled with Hadoop. Make sure the hadoop .so is + accessible when you start HBase. One means of doing this is after figuring your + platform, see <xref linkend="hbase.native.platform" />, make a symlink from HBase + to the native Hadoop libraries presuming the two software installs are colocated. + For example, if my 'platform' is Linux-amd64-64: + <programlisting>$ cd $HBASE_HOME +$ mkdir lib/native +$ ln -s $HADOOP_HOME/lib/native lib/native/Linux-amd64-64</programlisting> + Use the compression tool to check lz4 installed on all nodes. + Start up (or restart) hbase. From here on out you will be able to create + and alter tables to enable LZ4 as a compression codec. E.g.: + <programlisting>hbase(main):003:0> alter 'TestTable', {NAME => 'info', COMPRESSION => 'LZ4'}</programlisting> + </para> + </section> + <section xml:id="lzo.compression"> <title> LZO @@ -4395,20 +4457,6 @@ This option should not normally be used, and it is not in <code>-fixAll</code>. for a feature to help protect against failed LZO install.</para> </section> - <section xml:id="gzip.compression"> - <title> - GZIP - </title> - <para> - GZIP will generally compress better than LZO though slower. - For some setups, better compression may be preferred. - Java will use java's GZIP unless the native Hadoop libs are - available on the CLASSPATH; in this case it will use native - compressors instead (If the native libs are NOT present, - you will see lots of <emphasis>Got brand-new compressor</emphasis> - reports in your logs; see <xref linkend="brand.new.compressor" />). - </para> - </section> <section xml:id="snappy.compression"> <title> SNAPPY
