MySQL Cluster MaxNoOfConcurrentOperations and RAM Why increasing of MaxNoOfConcurrentOperations lead to higher consumption of RAM? 

I need high value for fast filling tables with some random data, but i noticed that my datanodes are swapping at starting with high values (5,000,000 - 10,000,000). 

There is another way to solve it: use innodb then alter table, but there might be other difficulties (some people complain about "lock wait timeout exceeded"). 

I just want to know how it working and how number of operations tied with RAM.
This is a good summary: http://fromdual.com/mysql-cluster-memory-sizing 

Most memory buffers are preallocated in memory to avoid latency issues when reserving huge chunks of memory.