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From Nguyen Kien Trung <trung....@gmail.com>
Subject Re: Safe mode is ON
Date Wed, 11 Jul 2007 01:44:13 GMT
Thanks Konstantin. I understand now

" At startup the name node accepts data node reports collecting 
information about block locations. In order to leave safe mode it needs 
to collect a configurable percentage called threshold of blocks, which 
satisfy the minimal replication condition. The minimal replication 
condition is that each block must have at least dfs.replication.min 
replicas. When the threshold is reached the name node extends safe mode 
for a configurable amount of time to let the remaining data nodes to 
check in before it will start replicating missing blocks. Then the name 
node leaves safe mode."

I realized that lots of blocks are missing their replicas. And that 
turns into the situation of SAFE mode.
Does it make sense to allow the command ./hadoop dfs -setrep to work 
even the name node is in safe mode? Otherwise the name node is idle forever

Konstantin Shvachko wrote:
> You can run "hadoop fsck / " to see how many blocks are missing on 
> your cluster.
> See definition of safe mode here.
> http://lucene.apache.org/hadoop/api/org/apache/hadoop/dfs/NameNode.html#setSafeMode(org.apache.hadoop.dfs.FSConstants.SafeModeAction)

> --Konstantin
> erolagnab wrote:
>> Hi all,
>> Just wondering what is the reason causing NameNode is on SafeMode 
>> forever?
>> I've left my machine running for 2 days and it's still on Safe Mode.
>> Trung

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