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From Shumin Guo <gsmst...@gmail.com>
Subject Re: Issue: Namenode is in safe mode
Date Wed, 06 Mar 2013 16:30:18 GMT
To decommission a live datanode from the cluster, you can do the following
steps:

1, edit configuration file $HADOOP_HOME/conf/hdfs-site.xml, and add the
following property:
<property>
<name>dfs.hosts.exclude</name>
<value>$HADOOP_HOME/conf/dfs-exclude.txt</value>
</property>

2, put the host name of the node you want to decommission onto file
$HADOOP_HOME/conf/dfs-exclude.xml (one host per line).

3, Run the following command:
hadoop dfsadmin -refreshNodes

Shumin

On Wed, Mar 6, 2013 at 5:29 AM, AMARNATH, Balachandar <
BALACHANDAR.AMARNATH@airbus.com> wrote:

> The repliation factor was 1 when I removed the entry of A in slaves file.
> I did not mark it retirement. I do not know yet how to mark a node for
> retirement. I waited for few minutes and then I could see thte namenode
> running again****
>
> ** **
>
> *From:* Nitin Pawar [mailto:nitinpawar432@gmail.com]
> *Sent:* 06 March 2013 15:31
> *To:* user@hadoop.apache.org
> *Subject:* Re: Issue: Namenode is in safe mode****
>
> ** **
>
> what is your replication factor?****
>
> when you removed node A as datanode .. did you first mark it for
> retirement? if you just removed it from service then the blocks from that
> datanode are missing and namenode when starts up it checks for the blocks.
> Unless it reaches its threshold value it will not let you write any more
> data on your hdfs. ****
>
> ** **
>
> I will suggest to start datanode on A, then mark it for retirement so
> namenode will move the blocks to new datanode and once it is done namenode
> will retire that datanode. ****
>
> ** **
>
> ** **
>
> ** **
>
> On Wed, Mar 6, 2013 at 3:21 PM, AMARNATH, Balachandar <
> BALACHANDAR.AMARNATH@airbus.com> wrote:****
>
>  ****
>
> Hi, ****
>
>  ****
>
> I have created a hadoop cluster with two nodes (A and B). ‘A’ act both as
> namenode and datanode, and ‘B’ act as datanode only. With this setup, I
> could store, read files. Now, I added one more datanode ‘C’ and relieved
> ‘A’ from datanode duty. This means, ‘A’ act only as namenode, and both B
> and C act as datanodes. Now, I tried to create a directory, it says****
>
>  ****
>
> ‘ org.apache.hadoop.hdfs.server.namenode.SafeModeException: Cannot create
> directory Name node is in safe mode’****
>
>  ****
>
>  ****
>
> Can someone tell me why the namenode now is in safe mode?****
>
>  ****
>
> With thanks and regards****
>
> Balachandar****
>
>  ****
>
>  ****
>
>  ****
>
> The information in this e-mail is confidential. The contents may not be disclosed or
used by anyone other than the addressee. Access to this e-mail by anyone else is unauthorised.****
>
> If you are not the intended recipient, please notify Airbus immediately and delete this
e-mail.****
>
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as it has been sent over public networks. If you have any concerns over the content of this
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>
>
> ****
>
> ** **
>
> --
> Nitin Pawar****
>
> The information in this e-mail is confidential. The contents may not be disclosed or
used by anyone other than the addressee. Access to this e-mail by anyone else is unauthorised.
> If you are not the intended recipient, please notify Airbus immediately and delete this
e-mail.
> Airbus cannot accept any responsibility for the accuracy or completeness of this e-mail
as it has been sent over public networks. If you have any concerns over the content of this
message or its Accuracy or Integrity, please contact Airbus immediately.
> All outgoing e-mails from Airbus are checked using regularly updated virus scanning software
but you should take whatever measures you deem to be appropriate to ensure that this message
and any attachments are virus free.
>
>

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