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From aaron morton <>
Subject Re: Row caching memory usage in Cassandra 1.0.x
Date Tue, 23 Oct 2012 00:24:15 GMT
I'm not aware of how to track the memory usage for the off heap row cache in 1.0. The memory
may show up in something like JConsole. What about seeing how much os memory is allocated
to buffers and working backwards from there?   

Anyone else ? 

(One thing to be away of is each CF has it's own row cache, so tuning must be done per CF.

Aaron Morton
Freelance Developer

On 23/10/2012, at 3:35 AM, Josh <> wrote:

> Hi, I'm hoping to get some help on how to help tune our 1.0.x cluster w.r.t. row 
> caching.
> We're using the netflix priam client, so unfortunately upgrading to 1.1.x is out 
> of the question for now.. but until we find a way around that, is there any way 
> to help determine where the 'sweet spot' is between heap size, row cache size, 
> and leaving the rest of the ram available to the OS?
> We're using the oracle jvm with jna so we can do the off-heap row caching, but 
> I'm not sure how to tell how much ram it's using, thus I'm not comfortable 
> increasing it further. (currently we have it set to 100,000 rows and we're 
> already seeing ~85% hit rates, so we've stopped upping it further for now).
> Thanks for any advice,
> -Josh

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