Hi Hadoopers,

I have
<property>
    <name>dfs.replication</name>
    <value>2</value>
    <final>true</final>
  </property>

set in hdfs-site.xml in staging environment cluster. while the staging
cluster is running the code that will later be deployed in production,
those code is trying to have dfs.replication of 3, 10, 50, other than
2; the number that developer thought that will fit in production
environment.

Even though I final the property dfs.replication in staging cluster
already. every time i run fsck on the staging cluster i still see it
said under replication.
I thought final keyword will not honor value in job config, but it
doesn't seem so when i run fsck.

I am on cdh3u4.

please suggest.
Patai

Hi Patai,

Set the dfs.replication.max parameter to 2 to achieve what you want.

On Tue, Oct 16, 2012 at 12:31 AM, Patai Sangbutsarakum
<[EMAIL PROTECTED]> wrote:
> Hi Hadoopers,
>
> I have
> <property>
>     <name>dfs.replication</name>
>     <value>2</value>
>     <final>true</final>
>   </property>
>
> set in hdfs-site.xml in staging environment cluster. while the staging
> cluster is running the code that will later be deployed in production,
> those code is trying to have dfs.replication of 3, 10, 50, other than
> 2; the number that developer thought that will fit in production
> environment.
>
> Even though I final the property dfs.replication in staging cluster
> already. every time i run fsck on the staging cluster i still see it
> said under replication.
> I thought final keyword will not honor value in job config, but it
> doesn't seem so when i run fsck.
>
> I am on cdh3u4.
>
> please suggest.
> Patai

--
Harsh J

Hello Patai,

Has your configuration file change been copied to all nodes in the cluster?

Are there applications connecting from outside of the cluster?  If so, then
those clients could have separate configuration files or code setting
dfs.replication (and other configuration properties).  These would not be
limited by final declarations in the cluster's configuration files.
 <final>true</final> controls configuration file resource loading, but it
does not necessarily block different nodes or different applications from
running with completely different configurations.

Hope this helps,
--Chris

On Mon, Oct 15, 2012 at 12:01 PM, Patai Sangbutsarakum <
[EMAIL PROTECTED]> wrote:

> Hi Hadoopers,
>
> I have
> <property>
>     <name>dfs.replication</name>
>     <value>2</value>
>     <final>true</final>
>   </property>
>
> set in hdfs-site.xml in staging environment cluster. while the staging
> cluster is running the code that will later be deployed in production,
> those code is trying to have dfs.replication of 3, 10, 50, other than
> 2; the number that developer thought that will fit in production
> environment.
>
> Even though I final the property dfs.replication in staging cluster
> already. every time i run fsck on the staging cluster i still see it
> said under replication.
> I thought final keyword will not honor value in job config, but it
> doesn't seem so when i run fsck.
>
> I am on cdh3u4.
>
> please suggest.
> Patai
>

Hey Chris,

The dfs.replication param is an exception to the <final> config
feature. If one uses the FileSystem API, one can pass in any short
value they want the replication to be. This bypasses the
configuration, and the configuration (being per-file) is also client
sided.

The right way for an administrator to enforce a "max" replication
value at a create/setRep level, would be to set
the dfs.replication.max to a desired value at the NameNode and restart
it.

On Tue, Oct 16, 2012 at 12:48 AM, Chris Nauroth
<[EMAIL PROTECTED]> wrote:
> Hello Patai,
>
> Has your configuration file change been copied to all nodes in the cluster?
>
> Are there applications connecting from outside of the cluster?  If so, then
> those clients could have separate configuration files or code setting
> dfs.replication (and other configuration properties).  These would not be
> limited by final declarations in the cluster's configuration files.
> <final>true</final> controls configuration file resource loading, but it
> does not necessarily block different nodes or different applications from
> running with completely different configurations.
>
> Hope this helps,
> --Chris
>
>
> On Mon, Oct 15, 2012 at 12:01 PM, Patai Sangbutsarakum
> <[EMAIL PROTECTED]> wrote:
>>
>> Hi Hadoopers,
>>
>> I have
>> <property>
>>     <name>dfs.replication</name>
>>     <value>2</value>
>>     <final>true</final>
>>   </property>
>>
>> set in hdfs-site.xml in staging environment cluster. while the staging
>> cluster is running the code that will later be deployed in production,
>> those code is trying to have dfs.replication of 3, 10, 50, other than
>> 2; the number that developer thought that will fit in production
>> environment.
>>
>> Even though I final the property dfs.replication in staging cluster
>> already. every time i run fsck on the staging cluster i still see it
>> said under replication.
>> I thought final keyword will not honor value in job config, but it
>> doesn't seem so when i run fsck.
>>
>> I am on cdh3u4.
>>
>> please suggest.
>> Patai
>
>

--
Harsh J