On 01/17/2013 08:58 AM, Mohammad Tariq wrote:
Hello Glen,
Pl find my comments embedded below :
1.) The Standalone Operation
(http://hadoop.apache.org/docs/r1.1.1/single_node_setup.html#Local),
just to confirm, can run without any DFS filesystem? (We're not being
asked to run "bin/hadoop namenode -format" for it.)
>>Yes. You don't need HDFS for this.
2.) For Pseudo-Distributed Operation
(http://hadoop.apache.org/docs/r1.1.1/single_node_setup.html#PseudoDistributed),
where we are instructed to run "bin/hadoop namenode -format",
question: how do I undo whatever that command does? I.e., how do I
delete that distributed file system created as well as remove from
Hadoop any knowledge of its prior existence -- do I have to manually
delete files with OS commands (what do I remove?) or is there some
type of "bin/hadoop namenode -delete" command that undoes the
"-format" command?
>>You can reformat the NameNode or manually delete the directories holding
the data and the metadata.
Thanks, Tariq, looking at the output of the namenode -format command it
looks like the only folder I have to delete is /tmp/hadoop-gmazza:
13/01/17 09:45:08 INFO namenode.FSEditLog: closing edit log: position=4,
editlog=/tmp/hadoop-gmazza/dfs/name/current/edits
13/01/17 09:45:08 INFO namenode.FSEditLog: close success: truncate to 4,
editlog=/tmp/hadoop-gmazza/dfs/name/current/edits
13/01/17 09:45:08 INFO common.Storage: Storage directory
/tmp/hadoop-gmazza/dfs/name has been successfully formatted.
Question: Why does Hadoop place the dfs folder under /tmp? It's subject
that way to getting erased each time I reboot my computer. Looking at
the instructions for namenode -format:
http://hadoop.apache.org/docs/r1.1.0/commands_manual.html#namenode, it
doesn't appear we have an option to specify where we would like the dfs
folder to be created.
Thanks,
Glen
Warm Regards,
Tariq
https://mtariq.jux.com/
cloudfront.blogspot.com <http://cloudfront.blogspot.com>
On Thu, Jan 17, 2013 at 7:24 PM, Glen Mazza <[email protected]
<mailto:[email protected]>> wrote:
Hi, I'm following the Hadoop 1.1.1 tutorial
(http://hadoop.apache.org/docs/r1.1.1/single_node_setup.html) and
I have these questions:
1.) The Standalone Operation
(http://hadoop.apache.org/docs/r1.1.1/single_node_setup.html#Local),
just to confirm, can run without any DFS filesystem? (We're not
being asked to run "bin/hadoop namenode -format" for it.)
2.) For Pseudo-Distributed Operation
(http://hadoop.apache.org/docs/r1.1.1/single_node_setup.html#PseudoDistributed),
where we are instructed to run "bin/hadoop namenode -format",
question: how do I undo whatever that command does? I.e., how do
I delete that distributed file system created as well as remove
from Hadoop any knowledge of its prior existence -- do I have to
manually delete files with OS commands (what do I remove?) or is
there some type of "bin/hadoop namenode -delete" command that
undoes the "-format" command?
Thanks,
Glen
--
Glen Mazza
Talend Community Coders - coders.talend.com <http://coders.talend.com>
blog: www.jroller.com/gmazza <http://www.jroller.com/gmazza>
--
Glen Mazza
Talend Community Coders - coders.talend.com
blog: www.jroller.com/gmazza
