Using off jvm heap as memory area

Question

Hi,
I am using Oracle Coherence 3.6.1 within Oracle CEP. I want to use Oracel Coherence out of the JVM so I want to use nio-memory-manager. My data size more than 10gb and I want to place this data into the memory. How can I perform this by using nio-memory-manager in coherence-cache-config.xml ?
Thanks.

Answer 1

I also agree that 10Gig is no big deal. Assuming you want at least two physical servers (to get redundancy!) and that you can hardly get a server with less than 4 cores & 16 gig RAM today (with new hardware 6 - 8 cores is common) you can run 4-6 nodes each with say 2-gig heap size each on each of the two server (remember that id the dataset is 10 gig you need to hold another 10 gig for backup data).
The real problem comes when you have like 500+ gig data and want to make use of say 6-8 core servers with 128 or 256 gig RAM - then the number of JVMs per server (if you want to keep the heap size down to say 2-3 gig) becomes much higher than your number of cores and processing is no longer performed in parallel...
In these situations you must today either accept the reduced performance from non-parallel execution, a higher cost (buy a larger number of physical servers and pay for more Coherence licenses) or look into using off-heap storage and/or avoid holding the complete dataset in memory (using a cache store / loader)...
There is however another message in this thread where Cameron reported positive experiences with really large heaps and CMS garbage collector so there may still be hope for holding very large datasets in an economical way if you are prepared to do some GC-tuning... :-)
/Magnus
Edited by: MagnusE on Feb 7, 2011 9:38 AM