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From Fang Zhou <timchou....@gmail.com>
Subject Re: How can I get the memory usage in Namenode and Datanode?
Date Sun, 22 Feb 2015 06:39:45 GMT
Can anyone help me?

Thanks,
Tim

> On Feb 21, 2015, at 2:54 PM, Fang Zhou <TIMCHOU.HIT@GMAIL.COM> wrote:
> 
> Hi All,
> 
> I want to test the memory usage on Namenode and Datanode.
> 
> I try to use jmap, jstat, proc/pid/stat, top, ps aux, and Hadoop website interface to
check the memory.
> The values I get from them are different. I also found that the memory always changes
periodically.
> This is the first thing confused me.
> 
> I thought the more files stored in Namenode, the more memory usage in Namenode and Datanode.
> I also thought the memory used in Namenode should be larger than the memory used in each
Datanode.
> However, some results show my ideas are wrong.
> For example, I test the memory usage of Namenode with 6000 and 1000 files.
> The "6000” memory is less than “1000” memory from jmap’s results. 
> I also found that the memory usage in Datanode is larger than the memory used in Namenode.
> 
> I really don’t know how to get the memory usage in Namenode and Datanode.
> 
> Can anyone give me some advices?
> 
> Thanks,
> Tim


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