After you added the nodes back to your cluster you run the balancer tool, but it will not bring in exactly the same blocks like before.
Cheers, Mirko 2014-07-24 17:34 GMT+01:00 andrew touchet <adt...@latech.edu>: > Thanks for the reply, > > I am using Hadoop-0.20. We installed from Apache not cloundera, if that > makes a difference. > > Currently I really need to know how to get the data that was replicated > during decommissioning back onto my two data nodes. > > > > > > On Thursday, July 24, 2014, Stanley Shi <s...@gopivotal.com> wrote: > >> which distribution are you using? >> >> Regards, >> *Stanley Shi,* >> >> >> >> On Thu, Jul 24, 2014 at 4:38 AM, andrew touchet <adt...@latech.edu> >> wrote: >> >>> I should have added this in my first email but I do get an error in the >>> data node's log file >>> >>> '2014-07-12 19:39:58,027 INFO >>> org.apache.hadoop.hdfs.server.datanode.DataNode: BlockReport of 0 blocks >>> got processed in 1 msecs' >>> >>> >>> >>> On Wed, Jul 23, 2014 at 3:18 PM, andrew touchet <adt...@latech.edu> >>> wrote: >>> >>>> Hello, >>>> >>>> I am Decommissioning data nodes for an OS upgrade on a HPC cluster . >>>> Currently, users can run jobs that use data stored on /hdfs. They are able >>>> to access all datanodes/compute nodes except the one being decommissioned. >>>> >>>> Is this safe to do? Will edited files affect the decommissioning node? >>>> >>>> I've been adding the nodes to /usr/lib/hadoop-0.20/conf/hosts_exclude >>>> and running 'hadoop dfsadmin -refreshNodes' on the name name node. Then >>>> I simply wait for log files to report completion. After upgrade, I simply >>>> remove the node from hosts_exlude and start hadoop again on the datanode. >>>> >>>> Also: Under the namenode web interface I just noticed that the node I >>>> have decommissioned previously now has 0 Configured capacity, Used, >>>> Remaining memory and is now 100% Used. >>>> >>>> I used the same /etc/sysconfig/hadoop file from before the upgrade, >>>> removed the node from hosts_exclude, and ran '-refreshNodes' afterwards. >>>> >>>> What steps have I missed in the decommissioning process or while >>>> bringing the data node back online? >>>> >>>> >>>> >>>> >>> >>
