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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: Off-heap row cache and mmapped sstables
Date Wed, 18 Apr 2012 02:55:14 GMT
Absolutely.  Best practice is still to disable swap entirely on server
machines; mlockall is just our best attempt to at least keep your JVM
from swapping if you've forgotten this.

On Thu, Apr 12, 2012 at 11:15 AM, Omid Aladini <omidaladini@gmail.com> wrote:
> Hi,
>
> Cassandra issues an mlockall [1] before mmap-ing sstables to prevent
> the kernel from paging out heap space in favor of memory-mapped
> sstables. I was wondering, what happens to the off-heap row cache
> (saved or unsaved)? Is it possible that the kernel pages out off-heap
> row cache in favor of resident mmap-ed sstable pages?
>
> Thanks,
> Omid
>
> [1] http://pubs.opengroup.org/onlinepubs/007908799/xsh/mlockall.html



-- 
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of DataStax, the source for professional Cassandra support
http://www.datastax.com

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