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From "donhoff_h" <165612...@qq.com>
Subject Re: Snappy Configuration in Hadoop2.5.2
Date Mon, 16 Mar 2015 06:54:32 GMT
Hi, Azuryy.

Thanks for your reply. 

Is there any way which does not require to copy the snappy libs? I mean is there any environment
variable that I can configure so that I don't have to copy the snappy libs. I have tried JAVA_LIBRARY_PATH
and LD_LIBRARY_PATH. But they didn't work.




------------------ Original ------------------
From:  "Azuryy Yu";<azuryyyu@gmail.com>;
Send time: Monday, Mar 16, 2015 2:43 PM
To: "user@hadoop.apache.org"<user@hadoop.apache.org>; 

Subject:  Re: Snappy Configuration in Hadoop2.5.2



Hi,
please :
run "cp -a /opt/snappy/lib/libsnappy.* /opt/hadoop/hadoophome/lib/native" on each datanode.
also you need to install Snappy on each datanode firstly.














On Sat, Mar 7, 2015 at 6:57 PM, donhoff_h <165612158@qq.com> wrote:
Hi, experts.

I meet the following problem when configuring the Snappy lib in Hadoop2.5.2

My snappy installation home is /opt/snappy
My Hadoop installation home is /opt/hadoop/hadoophome

To configure the snappy path, I tried to add the following environment variables in /etc/profile
and hadoop-env.sh :
export JAVA_LIBRARY_PATH=/opt/hadoop/hadoophome/lib/native:/opt/snappy/lib
export LD_LIBRARY_PATH=/opt/hadoop/hadoophome/lib/native:/opt/snappy/lib‍

After the configuration, I ran the command "hadoop checknative". The result showed as following
which I think means the hadoop can find the snappy lib:
Native library checking:
hadoop: true /opt/hadoop/hadoop-2.5.2/lib/native/libhadoop.so.1.0.0
zlib:   true /lib64/libz.so.1
snappy: true /opt/snappy/lib/libsnappy.so.1
lz4:    true revision:99
bzip2:  false‍

But when I ran a MapReduce Job, it reported the following error:
Error: java.lang.RuntimeException: native snappy library not available: SnappyCompressor has
not been loaded.
    at org.apache.hadoop.io.compress.SnappyCodec.checkNativeCodeLoaded(SnappyCodec.java:69)
    at org.apache.hadoop.io.compress.SnappyCodec.createCompressor(SnappyCodec.java:143)
    at org.apache.hadoop.io.compress.SnappyCodec.createOutputStream(SnappyCodec.java:98)
    at org.apache.hadoop.mapreduce.lib.output.TextOutputFormat.getRecordWriter(TextOutputFormat.java:136)‍

I also tried to set io.compression.codecs, but it did not work too.

The only way I found worked is to make a soft link as following:
ln -s /opt/snappy/lib/libsnappy.so.1.2.1 /opt/hadoop/hadoophome/lib/native/libsnappy.so.1

I used to config snappy in Hadoop2.4.0 successfully. I remembered that I only need to config
the LD_LIBRARY_PATH in /etc/profile. There is no need to make a such soft link. Does Hadoop2.5.2
not support this configuration anymore? Or is there other ways to config in Hadoop2.5.2 which
don't require to make links or have to copy the lib to the hadoop's lib/native directory?

Many Thanks!
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