hadoop-common-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Stanley Shi <s...@pivotal.io>
Subject Re: Hadoop on Safe Mode because Resources are low on NameNode
Date Wed, 27 Aug 2014 04:08:25 GMT
You can force the namenode to get out of safe mode: hadoop dfsadmin
-safemode leave


On Tue, Aug 26, 2014 at 11:05 PM, Vincent Emonet <vincent.emonet@gmail.com>
wrote:

> Hello,
>
> We have a 11 nodes Hadoop cluster installed from Hortonworks RPM doc:
>
> http://docs.hortonworks.com/HDPDocuments/HDP2/HDP-2.0.9.1/bk_installing_manually_book/content/rpm-chap1.html
>
> The cluster was working fine since it went on Safe Mode during the
> execution of a job with this message on the NameNode interface:
>
>
>
> *Safe mode is ON. Resources are low on NN. Please add or free up more
> resources then turn off safe mode manually. NOTE: If you turn off safe mode
> before adding resources, the NN will immediately return to safe mode. Use
> "hdfs dfsadmin -safemode leave" to turn safe mode off.*
> The error displayed in the job log is:
> 2014-08-22 08:51:35,446 WARN namenode.NameNodeResourceChecker
> (NameNodeResourceChecker.java:isResourceAvailable(89)) - Space available on
> volume 'null' is 100720640, which is below the configured reserved amount
> 104857600 2014-08-22 08:51:35,446 WARN namenode.FSNamesystem
> (FSNamesystem.java:run(4042)) - NameNode low on available disk space.
> Already in safe mode.
>
> On each node we have 5 hdd used for Hadoop
> And we checked the 5 hdd on the namenode are all full (between 95 and
> 100%) when the HDFS as still 50% of its capacity available : on the other
> nodes the 5 hdd are at 30/40%
>
> So I think this is the cause of the error.
>
> On the NameNode we had some Non HDFS data on 1 hdd, so I deleted them to
> have 50% of this hdd available (the 4 others are still between 95 and 100%)
> But this didn't resolve the problem
> I have also followed the advices found here :
> https://issues.apache.org/jira/browse/HDFS-4425
> And added the following property to the hdfs-site.xml of the NameNode
> (multiplying the default value by 2)
>   <property>
>      <name>dfs.namenode.resource.du.reserved</name>
>        <value>209715200</value>
>    </property>
>
> Still impossible to get out of the safe mode and as log as we are in safe
> mode we can't delete anything in the HDFS.
>
>
> Is anyone having a tip about this issue?
>
>
> Thankfully,
>
> Vincent.
>
>
>


-- 
Regards,
*Stanley Shi,*

Mime
View raw message