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MapReduce, mail # user - dynamically resizing the Hadoop cluster?


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Nan Zhu 2013-10-24, 03:35
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Re: dynamically resizing the Hadoop cluster?
Ravi Prakash 2013-10-24, 18:04
Hi Nan!

Usually nodes are decommissioned slowly over some period of time so as not to disrupt the running jobs. When a node is decommissioned, the NameNode must re-replicate all under-replicated blocks. Rather than suddenly remove half the nodes, you might want to take a few nodes offline at a time. Hadoop should be able to handle rescheduling tasks on nodes no longer available (even without speculative execution. Speculative execution is for something else).
HTH
Ravi
On Wednesday, October 23, 2013 10:26 PM, Nan Zhu <[EMAIL PROTECTED]> wrote:
 
Hi, all

I’m running a Hadoop cluster on AWS EC2, 

I would like to dynamically resizing the cluster so as to reduce the cost, is there any solution to achieve this? 

E.g. I would like to cut the cluster size with a half, is it safe to just shutdown the instances (if some tasks are just running on them, can I rely on the speculative execution to re-run them on the other nodes?)

I cannot use EMR, since I’m running a customized version of Hadoop 

Best,

-- 
Nan Zhu
School of Computer Science,
McGill University
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Nan Zhu 2013-10-24, 18:20
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Ravi Prakash 2013-10-24, 20:51
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Nan Zhu 2013-10-24, 21:07