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From Sean Owen <sro...@gmail.com>
Subject Re: Memory. -Xmx. error=12, chmod, JobTracker.
Date Fri, 11 Dec 2009 11:52:57 GMT
"-Xmx900" means "give the entire JVM only 900 bytes of heap space"
which can't possibly work.

You do not say what problem you are trying to solve here. What is the
problem when you do not mess with these options?

On Fri, Dec 11, 2009 at 3:05 PM, pavel kolodin
<pavelkolodinhadoop@gmail.com> wrote:
>
> Hello.
> I am running 0.20.1.
> There is an options HADOOP_*_OPTS in file hadoop-env.sh.
> When i don't put "-Xmx" in them at all, java can't initialize any VM at all.
> But this happens only on 64bit VPS with 3.5G RAM. Starting hadoop on my
> 32-bit laptop with 2GB ram and same hadoop-env.sh works fine.
>
> I am starting to play with "-Xmx" putting them to HADOOP_*_OPTS in file
> hadoop-env.sh.
> For example, the JobTracker's log files have records about error=12 (can't
> allocate mem for running "chmod"). Then i putting "-Xmx900" in
> HADOOP_JOBTRACKER_OPTS and errors=12 dont appear in JobTracker's logfiles
> anymore. Maybe a little :) But i don't understand, how -Xmx900 effects on
> java processes, because "900 bytes" can't be a big deal) If i try to write
> "-Xmx900M" then VM can't initialize again. Then i trying to write "-Xmx128".
> Now JobTracker again says "error=12, memory, chmod, etc...". If i increasing
> the number of megabytes, error=12 don't disappear but the moment "cant
> initialize VM" comes again)
> Maybe i am touching wrong option (HADOOP_JOBTRACKER_OPTS)?
> Thank you.
>

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