Is there any way I can configure KeyCahce to use Non-Heap memory ? 
No.
You could add a feature request here https://issues.apache.org/jira/browse/CASSANDRA

Could you post some stats on the current key cache size and hit rate ? (from nodetool info) 
It would be interesting to know how many keys it contains Vs the number of rows on the box and the hit rate. 

Cheers

-----------------
Aaron Morton
Freelance Developer
@aaronmorton

On 4/09/2012, at 3:01 PM, Ananth Gundabattula <agundabattula@threatmetrix.com> wrote:


Is there any way I can configure KeyCahce to use Non-Heap memory ? 

We have large memory nodes :  ~96GB memory per node and effectively using only  8 GB configured for heap ( to avoid GC issues because of a large heap) 

We have a constraint with respect to : 
  1. Row cache models don't reflect our data query patterns and hence can only optimize on the key cache 
  2. Time constrained to change our schema to be more NO-SQL specific


Regards,
Ananth