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From Bejoy Ks <bejoy.had...@gmail.com>
Subject Re: Hadoop filesystem directories not visible
Date Thu, 19 Jul 2012 10:18:31 GMT
This can be good reference to start with
http://wiki.apache.org/hadoop/HadoopDfsReadWriteExample

On Thu, Jul 19, 2012 at 3:42 PM, Mohammad Tariq <dontariq@gmail.com> wrote:
> Hi Yuvraj,
>
>       Yes. The starting point for the Hadoop file API is the
> 'FileSystem' class. Hadoop’s FileSystem provides the us with
> FSDataInputStream and FSDataInputStream classes for reading and
> writing files.
>
>
> Regards,
>     Mohammad Tariq
>
>
> On Thu, Jul 19, 2012 at 3:31 PM, Yuvrajsinh Chauhan
> <yuvraj.chauhan@elitecore.com> wrote:
>> So, I understand that, If I want to write a file then I need to change the
>> code of my external application need to integrate Hadoop read-write
>> command/API.
>>
>>
>>
>> Regards,
>>
>> Yuvrajsinh Chauhan
>>
>>
>>
>> From: Saniya Khalsa [mailto:saniya.khalsa@gmail.com]
>> Sent: 19 July 2012 15:27
>> To: hdfs-user@hadoop.apache.org; bejoy.hadoop@gmail.com
>>
>>
>> Subject: Re: Hadoop filesystem directories not visible
>>
>>
>>
>> Thanks Bejoy!!
>>
>>
>> On Thu, Jul 19, 2012 at 3:22 PM, Bejoy KS <bejoy.hadoop@gmail.com> wrote:
>>
>> Hi Saniya
>>
>> In hdfs the directory exists only as meta data in the name node. There is no
>> real hierarchical existence like normal file system. It is the data in the
>> files that is stored as hdfs blocks distributed across data nodes. You see
>> these hdfs blocks arranged in dfs.data.dir .
>>
>> Regards
>> Bejoy KS
>>
>> Sent from handheld, please excuse typos.
>>
>> ________________________________
>>
>> From: "Yuvrajsinh Chauhan" <yuvraj.chauhan@elitecore.com>
>>
>> Date: Thu, 19 Jul 2012 15:16:24 +0530
>>
>> To: <hdfs-user@hadoop.apache.org>
>>
>> ReplyTo: hdfs-user@hadoop.apache.org
>>
>> Subject: RE: Hadoop filesystem directories not visible
>>
>>
>>
>> Dear Saniya,
>>
>>
>>
>> I Second to you on this. Am also find exactly the same folder on secondary
>> data node.
>>
>> Also, How can I write files from my external application ?
>>
>>
>>
>> Regards,
>>
>>
>>
>> Yuvrajsinh Chauhan || Sr. DBA || CRESTEL-PSG
>>
>> Elitecore Technologies Pvt. Ltd.
>>
>> 904, Silicon Tower || Off C.G.Road
>>
>> Behind Pariseema Building || Ahmedabad || INDIA
>>
>> [GSM]: +91 9727746022
>>
>>
>>
>> From: Saniya Khalsa [mailto:saniya.khalsa@gmail.com]
>> Sent: 19 July 2012 14:58
>> To: hdfs-user@hadoop.apache.org
>> Subject: Re: Hadoop filesystem directories not visible
>>
>>
>>
>> Hi Mohammad Tariq,
>>
>>
>>
>> Thanks for the reply!!
>>
>> The path to dfs.data.dir is /app/hadoop/tmp/dfs/data
>>
>> when i go there i find only these :
>>
>> BlocksBeingWriiten
>> Current
>> Detach
>> In_use.lock
>> storage
>> tmp
>>
>> I am unable to see the created directories here.
>>
>> Regards
>> Saniya
>>
>> On Thu, Jul 19, 2012 at 2:39 PM, Mohammad Tariq <dontariq@gmail.com> wrote:
>>
>> Hello Saniya,
>>
>>         If you are talking about the local FS, then it will be present
>> at the location specified as the value of 'dfs.data.dir' property in
>> hdfs-site.xml file.
>>
>> Regards,
>>     Mohammad Tariq
>>
>>
>>
>> On Thu, Jul 19, 2012 at 1:09 PM, Saniya Khalsa <saniya.khalsa@gmail.com>
>> wrote:
>>> Hi,
>>>
>>> I ran these commands
>>>
>>> $HADOOP_HOME/bin/hadoop fs -mkdir /tmp
>>> $HADOOP_HOME/bin/hadoop fs -mkdir /user
>>> The directories got created and I can now see the directories using
>>> following commands:
>>>
>>> [hadoop@master bin]$ ./hadoop fs -ls /
>>> Found 5 items
>>> drwxr-xr-x   - hadoop supergroup          0 2012-07-16 14:11 /app
>>> drwxr-xr-x   - hadoop supergroup          0 2012-07-17 17:41 /hadoop
>>> drwxr-xr-x   - hadoop supergroup          0 2012-07-18 14:11 /hbase
>>> drwxr-xr-x   - hadoop supergroup          0 2012-07-19 14:11 /tmp
>>> drwxr-xr-x   - hadoop supergroup          0 2012-07-19 17:41 /user
>>>
>>>
>>> I can see this data from both the nodes by typing the command ,but i
>>> cannot
>>> view  the directories created in the file path anywhere.Please tell me how
>>> to see these directories created in file system.
>>>
>>> Thanks
>>
>>
>>
>>

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