Will modification of one replica change other two replicas as well?












-1














Hadoop have 3 replication factor, right ?



If I modify one replica, will the other two replicas also change or not ?










share|improve this question





























    -1














    Hadoop have 3 replication factor, right ?



    If I modify one replica, will the other two replicas also change or not ?










    share|improve this question



























      -1












      -1








      -1







      Hadoop have 3 replication factor, right ?



      If I modify one replica, will the other two replicas also change or not ?










      share|improve this question















      Hadoop have 3 replication factor, right ?



      If I modify one replica, will the other two replicas also change or not ?







      hadoop






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited Nov 15 at 22:42









      cricket_007

      79.1k1142109




      79.1k1142109










      asked Nov 15 at 12:03









      Syed Furquan Ali

      11




      11
























          2 Answers
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          0














          But you can't modify the contents of file on hadoop because it is 'write once read many'.So,you first modify it locally and then replicate it on hdfs.So,then the contents of 3 replication are same.






          share|improve this answer





















          • In other words, you "overwrite" the file on HDFS with the local edits
            – cricket_007
            Nov 15 at 22:43










          • is there any way to overcome "overwrite" the file on HDFS @cricket_007.
            – code_cody97
            Nov 16 at 10:09





















          0














          By default, HDFS uses a replication factor equal to 3 but it can be changed. HDFS does not allow to alter just one copy of your data block, because block replication should be transparent for the user.



          Technically, you can alter one copy by accessing the local file system of a single datanode, and alter the files under the dfs.datanode.data.dir local direcory, but HDFS is not aware of this change, therfore it will not be replicated for the other copies.






          share|improve this answer





















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            2 Answers
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            2 Answers
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            active

            oldest

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            active

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            active

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            0














            But you can't modify the contents of file on hadoop because it is 'write once read many'.So,you first modify it locally and then replicate it on hdfs.So,then the contents of 3 replication are same.






            share|improve this answer





















            • In other words, you "overwrite" the file on HDFS with the local edits
              – cricket_007
              Nov 15 at 22:43










            • is there any way to overcome "overwrite" the file on HDFS @cricket_007.
              – code_cody97
              Nov 16 at 10:09


















            0














            But you can't modify the contents of file on hadoop because it is 'write once read many'.So,you first modify it locally and then replicate it on hdfs.So,then the contents of 3 replication are same.






            share|improve this answer





















            • In other words, you "overwrite" the file on HDFS with the local edits
              – cricket_007
              Nov 15 at 22:43










            • is there any way to overcome "overwrite" the file on HDFS @cricket_007.
              – code_cody97
              Nov 16 at 10:09
















            0












            0








            0






            But you can't modify the contents of file on hadoop because it is 'write once read many'.So,you first modify it locally and then replicate it on hdfs.So,then the contents of 3 replication are same.






            share|improve this answer












            But you can't modify the contents of file on hadoop because it is 'write once read many'.So,you first modify it locally and then replicate it on hdfs.So,then the contents of 3 replication are same.







            share|improve this answer












            share|improve this answer



            share|improve this answer










            answered Nov 15 at 14:50









            code_cody97

            709




            709












            • In other words, you "overwrite" the file on HDFS with the local edits
              – cricket_007
              Nov 15 at 22:43










            • is there any way to overcome "overwrite" the file on HDFS @cricket_007.
              – code_cody97
              Nov 16 at 10:09




















            • In other words, you "overwrite" the file on HDFS with the local edits
              – cricket_007
              Nov 15 at 22:43










            • is there any way to overcome "overwrite" the file on HDFS @cricket_007.
              – code_cody97
              Nov 16 at 10:09


















            In other words, you "overwrite" the file on HDFS with the local edits
            – cricket_007
            Nov 15 at 22:43




            In other words, you "overwrite" the file on HDFS with the local edits
            – cricket_007
            Nov 15 at 22:43












            is there any way to overcome "overwrite" the file on HDFS @cricket_007.
            – code_cody97
            Nov 16 at 10:09






            is there any way to overcome "overwrite" the file on HDFS @cricket_007.
            – code_cody97
            Nov 16 at 10:09















            0














            By default, HDFS uses a replication factor equal to 3 but it can be changed. HDFS does not allow to alter just one copy of your data block, because block replication should be transparent for the user.



            Technically, you can alter one copy by accessing the local file system of a single datanode, and alter the files under the dfs.datanode.data.dir local direcory, but HDFS is not aware of this change, therfore it will not be replicated for the other copies.






            share|improve this answer


























              0














              By default, HDFS uses a replication factor equal to 3 but it can be changed. HDFS does not allow to alter just one copy of your data block, because block replication should be transparent for the user.



              Technically, you can alter one copy by accessing the local file system of a single datanode, and alter the files under the dfs.datanode.data.dir local direcory, but HDFS is not aware of this change, therfore it will not be replicated for the other copies.






              share|improve this answer
























                0












                0








                0






                By default, HDFS uses a replication factor equal to 3 but it can be changed. HDFS does not allow to alter just one copy of your data block, because block replication should be transparent for the user.



                Technically, you can alter one copy by accessing the local file system of a single datanode, and alter the files under the dfs.datanode.data.dir local direcory, but HDFS is not aware of this change, therfore it will not be replicated for the other copies.






                share|improve this answer












                By default, HDFS uses a replication factor equal to 3 but it can be changed. HDFS does not allow to alter just one copy of your data block, because block replication should be transparent for the user.



                Technically, you can alter one copy by accessing the local file system of a single datanode, and alter the files under the dfs.datanode.data.dir local direcory, but HDFS is not aware of this change, therfore it will not be replicated for the other copies.







                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Nov 15 at 16:09









                54l3d

                3,08721437




                3,08721437






























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