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Re: some ideas for QJM and NFS
Oh, yes, you are right, George. I'll probably do it in the next days.
On Mon, Feb 18, 2013 at 2:47 PM, George Datskos <
[EMAIL PROTECTED]> wrote:

>  Hi Azuryy,
>
> So you have measurements for hadoop-1.0.4 and hadoop-2.0.3+QJM, but I
> think you should also measure hadoop-2.0.3 _wihout_ QJM so you can know for
> sure if the performance degrade is actually related to QJM or not.
>
>
> George
>
>
>   Hi,
>
>  HarshJ is a good guy, I've seen this JIRA:
> https://issues.apache.org/jira/browse/HDFS-4508
>
>  I have a test cluster hadoop-1.0.4, I've upgrade to hadoop-2.0.3-alpha.
> mu cluster is very small, four nodes totally.
>
>  then I did some test on the original Hadoop and new Hadoop, the testing
> is very simple: I have a data file with 450MB, I just put it on the HDFS.
>
>  block size: 128MB, replica: 2
>
>  the following is the result:
>
> [root@webdm test]# ll testspeed.tar.gz
> -rw-r--r-- 1 root root 452M Feb 18 13:54 testspeed.tar.gz
> [root@webdm test]#
>
>  //On the hadoop-1.0.4
>  [root@webdm test]# date +%Y-%m-%d_%H:%M:%S; hadoop dfs -put
> testspeed.tar.gz / ; date +%Y-%m-%d_%H:%M:%S
> 2013-02-18_13:54:24
> Warning: $HADOOP_HOME is deprecated.
> 2013-02-18_13:54:58
>
>  //On the hadoop-2.0.3-alpha with QJM
>  [root@webdm test]# date +%Y-%m-%d_%H:%M:%S; hdfs dfs -put
> testspeed.tar.gz / ; date +%Y-%m-%d_%H:%M:%S
> 2013-02-18_14:13:29
> 13/02/18 14:13:30 WARN util.NativeCodeLoader: Unable to load native-hadoop
> library for your platform... using builtin-java classes where applicable
> 2013-02-18_14:14:33
>
>  I do think QJM HA feature affect the performance, because each writer
> from QJM, it will do: fence old writer; sync in-progress log; start new log
> segment; then write. only if writer received a successful response from a
> quorum of JNs, writer finished for this time.
>
>  But NFS HA just write log segment in the local and NFS, when it receive
> successful response from NFS, it finished this time.
>
>  So, I just suggest we always keep these two HA features in future, even
> in the stable release. which one should be used, which depends on yourself
> based on your infrastructure.
>
>  Thanks.
>
>
>