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

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 <[EMAIL PROTECTED]> 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

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 <[EMAIL PROTECTED]> 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 <[EMAIL PROTECTED]>
> 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
>

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:[EMAIL PROTECTED]]
Sent: 19 July 2012 14:58
To: [EMAIL PROTECTED]
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 <[EMAIL PROTECTED]> 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 <[EMAIL PROTECTED]>
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

 

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.

-----Original Message-----
From: "Yuvrajsinh Chauhan" <[EMAIL PROTECTED]>
Date: Thu, 19 Jul 2012 15:16:24
To: <[EMAIL PROTECTED]>
Reply-To: [EMAIL PROTECTED]
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:[EMAIL PROTECTED]]
Sent: 19 July 2012 14:58
To: [EMAIL PROTECTED]
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 <[EMAIL PROTECTED]> 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 <[EMAIL PROTECTED]>
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

 

Thanks Bejoy!!

On Thu, Jul 19, 2012 at 3:22 PM, Bejoy KS <[EMAIL PROTECTED]> 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" <[EMAIL PROTECTED]>
> *Date: *Thu, 19 Jul 2012 15:16:24 +0530
> *To: *<[EMAIL PROTECTED]>
> *ReplyTo: * [EMAIL PROTECTED]
> *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***
>
> *E**litecore** T**echnologies **P**vt. **L**td.*****
>
> 904, Silicon Tower || Off C.G.Road****
>
> Behind Pariseema Building || Ahmedabad || INDIA****
>
> [GSM]: +91 9727746022****
>
> ** **
>
> *From:* Saniya Khalsa [mailto:[EMAIL PROTECTED]]
> *Sent:* 19 July 2012 14:58
> *To:* [EMAIL PROTECTED]
> *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 <[EMAIL PROTECTED]>
> 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 <[EMAIL PROTECTED]>
> 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****
>
> ** **
>

Saniya n Yuvrajsinh,

     You can't find the actual directory structure. Though you can go
inside "current" directory and see the file blocks. And as far as
writing files to Hdfs is concerned you have to use the Hdfs API.
Regards,
    Mohammad Tariq
On Thu, Jul 19, 2012 at 3:22 PM, Bejoy KS <[EMAIL PROTECTED]> 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" <[EMAIL PROTECTED]>
> Date: Thu, 19 Jul 2012 15:16:24 +0530
> To: <[EMAIL PROTECTED]>
> ReplyTo: [EMAIL PROTECTED]
> 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:[EMAIL PROTECTED]]
> Sent: 19 July 2012 14:58
> To: [EMAIL PROTECTED]
> 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 <[EMAIL PROTECTED]> 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 <[EMAIL PROTECTED]>
> 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
>
>

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:[EMAIL PROTECTED]]
Sent: 19 July 2012 15:27
To: [EMAIL PROTECTED]; [EMAIL PROTECTED]
Subject: Re: Hadoop filesystem directories not visible

 

Thanks Bejoy!!
On Thu, Jul 19, 2012 at 3:22 PM, Bejoy KS <[EMAIL PROTECTED]> 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" <[EMAIL PROTECTED]>

Date: Thu, 19 Jul 2012 15:16:24 +0530

To: <[EMAIL PROTECTED]>

ReplyTo: [EMAIL PROTECTED]

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:[EMAIL PROTECTED]]
Sent: 19 July 2012 14:58
To: [EMAIL PROTECTED]
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 <[EMAIL PROTECTED]> 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 <[EMAIL PROTECTED]>
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

 

 

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
<[EMAIL PROTECTED]> 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:[EMAIL PROTECTED]]
> Sent: 19 July 2012 15:27
> To: [EMAIL PROTECTED]; [EMAIL PROTECTED]
>
>
> Subject: Re: Hadoop filesystem directories not visible
>
>
>
> Thanks Bejoy!!
>
>
> On Thu, Jul 19, 2012 at 3:22 PM, Bejoy KS <[EMAIL PROTECTED]> 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" <[EMAIL PROTECTED]>
>
> Date: Thu, 19 Jul 2012 15:16:24 +0530
>
> To: <[EMAIL PROTECTED]>
>
> ReplyTo: [EMAIL PROTECTED]
>
> 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:[EMAIL PROTECTED]]
> Sent: 19 July 2012 14:58
> To: [EMAIL PROTECTED]
> 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 <[EMAIL PROTECTED]> 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 <[EMAIL PROTECTED]>
> 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
>
>
>
>

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 <[EMAIL PROTECTED]> 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
> <[EMAIL PROTECTED]> 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:[EMAIL PROTECTED]]
>> Sent: 19 July 2012 15:27
>> To: [EMAIL PROTECTED]; [EMAIL PROTECTED]
>>
>>
>> Subject: Re: Hadoop filesystem directories not visible
>>
>>
>>
>> Thanks Bejoy!!
>>
>>
>> On Thu, Jul 19, 2012 at 3:22 PM, Bejoy KS <[EMAIL PROTECTED]> 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" <[EMAIL PROTECTED]>
>>
>> Date: Thu, 19 Jul 2012 15:16:24 +0530
>>
>> To: <[EMAIL PROTECTED]>
>>
>> ReplyTo: [EMAIL PROTECTED]
>>
>> 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:[EMAIL PROTECTED]]
>> Sent: 19 July 2012 14:58
>> To: [EMAIL PROTECTED]
>> 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 <[EMAIL PROTECTED]> 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 <[EMAIL PROTECTED]>
>> 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
>>
>>
>>
>>