Swapiness parameter configuration
The kernel parameter that determines the tendency of the kernel to swap pages in and out of the main memory is vm.swappiness. By default, on RHEL 7 and variants, the value is set to 60 (range 0-99). This is not appropriate for Hadoop clusters. This needs to be tuned down to 1 to avoid unnecessary page outs and long garbage collection pauses.
Run the following command to set the vm.swapiness parameter to 1:
sudo sysctl -w vm.swappiness=1
To make the vm.swapiness parameter persist across reboots, add an entry in the /etc/sysctl.conf file as follows: