SERVER CRASH - Unnecessary use of Swap in Couchbase 2.2.0 version , Even when memory is available

Whats your swappiness value?
#sysctl vm.swappiness

Whats your node config: memory of machine?

Whats how much memory is used by Couchbase data?

Do you have views? if so how many?

Are you running anything else on nodes besides CB?