Hadoop支持Lzo压缩配置及案例

Hadoop支持Lzo压缩配置及案例

hadoop支持Lzo压缩配置

1）hadoop本身并不支持lzo压缩，故需要使用twitter提供的hadoop-lzo开源组件。hadoop-lzo需依赖hadoop和lzo进行编译，编译步骤如下。2）将编译好后的hadoop-lzo-0.4.20.jar 放入hadoop-2.7.2/share/hadoop/common/

[atguigu@hadoop102 common]$ pwd/opt/module/hadoop-2.7.2/share/hadoop/common[atguigu@hadoop102 common]$ lshadoop-lzo-0.4.20.jar

3）同步hadoop-lzo-0.4.20.jar到hadoop103、hadoop104

[atguigu@hadoop102 common]$ xsync hadoop-lzo-0.4.20.jar

4）core-site.xml增加配置支持LZO压缩

io.compression.codecsorg.apache.hadoop.io.compress.GzipCodec,org.apache.hadoop.io.compress.DefaultCodec,org.apache.hadoop.io.compress.BZip2Codec,org.apache.hadoop.io.compress.SnappyCodec,com.hadoop.compression.lzo.LzoCodec,com.hadoop.compression.lzo.LzopCodec io.compression.codec.lzo.class com.hadoop.compression.lzo.LzoCodec

5）同步core-site.xml到hadoop103、hadoop104

[atguigu@hadoop102 hadoop]$ xsync core-site.xml

6）启动及查看集群

[atguigu@hadoop102 hadoop-2.7.2]$ sbin/start-dfs.sh[atguigu@hadoop103 hadoop-2.7.2]$ sbin/start-yarn.sh

7）创建lzo文件的索引，lzo压缩文件的可切片特性依赖于其索引，故我们需要手动为lzo压缩文件创建索引。若无索引，则lzo文件的切片只有一个。

hadoop jar /path/to/your/hadoop-lzo.jar  big_file.lzo

案例：以hadoop自带的wordcount为例mr输出结果为lzo格式1.创建word.txt文件,并写上几个单词上传到hdfs上[atguigu@hadoop202 bin]$ vim word.txt[atguigu@hadoop202 bin]$ hdfs dfs -put word.txt input2.运行wordcount案例

[atguigu@hadoop202 bin]$ hadoop jar /opt/module/hadoop-2.7.2/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.2.jar  wordcount -D mapreduce.output.fileoutputformat.compress=true -D maputformat.compress.codec=com.hadoop.compression.lzo.LzopCodec /input /output

[atguigu@hadoop202 bin]$ hadoop jar /opt/module/hadoop-2.7.2/share/hadoop/common/hadoop-lzo-0.4.20.jar  com.hadoop.compression.lzo.DistributedLzoIndexer  /output/part-r-00000.lzo

此时hdfs上会产生带有索引的lzo文件。