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From lohit <lohit...@yahoo.com>
Subject Re: How to exclude machines from a cluster
Date Thu, 13 Nov 2008 17:42:33 GMT

You could try to decommission the node. More information is provided here http://wiki.apache.org/hadoop/FAQ#17
When you request the NN to decommission a node, it tries to replicate all the blocks on that
node to different node. 

PS : 1 replica is always at risk of losing data, try atleast two, may be having the files
compressed might help.


----- Original Message ----
From: "Zhou, Yunqing" <azurezyq@gmail.com>
To: core-user@hadoop.apache.org
Sent: Thursday, November 13, 2008 1:06:00 AM
Subject: How to exclude machines from a cluster

Here is a cluster with 13 machines. And due to the lack of storage
space, we set the replication factor to 1.
but recently we found 2 machines in the cluster are not stable. so I'd
like to exclude them from the cluster.
but I can't simply set the replication factor to 1 and remove them due
to the large amount of data.
so is there a way I can force hadoop to move the block stored on them
to other machines?


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