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 <donta...@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.chau...@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.kha...@gmail.com] >> Sent: 19 July 2012 15:27 >> To: hdfs-user@hadoop.apache.org; bejoy.had...@gmail.com >> >> >> Subject: Re: Hadoop filesystem directories not visible >> >> >> >> Thanks Bejoy!! >> >> >> On Thu, Jul 19, 2012 at 3:22 PM, Bejoy KS <bejoy.had...@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.chau...@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.kha...@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 <donta...@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.kha...@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 >> >> >> >>
