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From "pavel kolodin" <pavelkolodinhad...@gmail.com>
Subject Re: Works on laptop with 2GB, but cannnot allocate memory on VPS with 3.5 GB.
Date Mon, 14 Dec 2009 06:04:57 GMT
> OpenVZ allows you to limit 6 different "kinds" of memory:
>             lockedpages
>             privvmpages
>             shmpages
>             physpages
>             vmguarpages
>             oomguarpages
> What exactly to do limit? "privvmpages"? Have you checked OpenVZ bean
> counters for processes hitting the limit in your VPSes?
> Generally, if we won't go into the details, OpenVZ "privvmpages" and
> having X megabytes of physical RAM in physical system is two very
> different things. If you use "privvmpages", you effectively limit the
> available address space of all processes inside VPS that they can
> _allocate_. Java applications are fairly sensitive to this - if, for
> example, you will run Java machines with -Xmx1024M in your "2.5GB RAM"
> VPS, and it's really "2.5GB worth of privvmpages", you'd likely would
> be able to run only 2 jvms: third one would fail mysteriously by
> hitting the limit.

Thank you for answer!
But i would like to see a little details. I will ask lame quesion :)
Why i can start more than two "java -Xmx1024M" on physically 2GB and can't
do it with OpenVZ's "provvmpages" 2GB?
Is it because kernel working with "physically" (native, pure..) RAM allows  
me to allocate more memory than i have ("allocate" not means "use", i  
understand), but when kernel working with that VPS's "provvmpages" RAM it  
cannot allow me to allocate more than i have? :)

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