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From Chris Burroughs <>
Subject Re: CMS GC initial-mark taking 6 seconds , bad?
Date Thu, 20 Oct 2011 17:34:43 GMT
On 10/20/2011 09:38 AM, Maxim Potekhin wrote:
> I happen to have 48GB on each machines I use in the cluster. Can I
> assume that I can't really use all of this memory productively? Do you
> have any suggestion related to that? Can I run more than one instance on
> Cassandra on the same box (using different ports) to take advantage of
> this memory, assuming the disk has enough bandwidth?

You are likely to not have good luck with a JVM heap that large.  But
you can:
 - Leave all that memory to the OS page cache.
 - mmap index files
 - use an off heap cache

All of those are productive uses.

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