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From Alain RODRIGUEZ <arodr...@gmail.com>
Subject Re: Tuning cassandra (compactions overall)
Date Wed, 16 May 2012 12:40:26 GMT
Using c1.medium, we are currently able to deliver the service.

What is the the benefit of having more memory ? I mean, I don't
understand why having 1, 2, 4, 8 or 16 GB of memory is so different.
In my mind, Cassandra will fill the heap and from then, start to flush
and compact to avoid OOMing and fill it again. The memory used inside
the heap will remains close to the max memory available, therefore
having more or less memory doesn't matter.

I'm pretty sure I misunderstand or forget something about how the
memory is used but not sure about what.

Can you enlighten me about this point ?

If I understand why the memory size is that important I will probably
be able to argue about the importance of having more memory and my
boss will probably allow me to spend more money to get better servers.

"There are some changes you can make to mitigate things (let me know
if you need help), but this is essentially a memory problem."

I'm interested a lot in learning about some configuration I can use to
reach better peformance/stability as well as in learning about how
Cassandra works.

Thanks for the help you give to people and for sharing your knowledge
with us. I appreciate a lot the Cassandra community and the most
active people keeping it alive. It's worth being said :).

Alain

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