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HDFS >> mail # dev >> RE: What does hdfs balancer do after adding more disks to existing datanode.


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RE: What does hdfs balancer do after adding more disks to existing datanode.
Hi,

Current volume choosing policy is round robin fashion, Since the DN got new disk, balancer will balance some blocks to this node. But the volume choosing will be same when palcing the block. AFAIK, it wont do any special balancing between disks in the same node. please correct me if i understood your question wrongly.

Regards,

Uma

From: Ajit Ratnaparkhi [[EMAIL PROTECTED]]
Sent: Tuesday, November 22, 2011 5:13 PM
To: [EMAIL PROTECTED]; [EMAIL PROTECTED]
Subject: What does hdfs balancer do after adding more disks to existing datanode.
Hi,

If I add additional disks to existing datanode (assume existing datanode has 7 1TB disk which are already 80% full and then I add two new 2TB disks 0% full) and then run balancer, does balancer balance data in a datanode? ie. Will it move data from existing disks to newly added disks such that all disks are approx equally full ?

thanks,
Ajit.
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB