Adjust the limits on the /dev/shm filesystem

You need to do this because Kognitio on Hadoop is an in-memory system.

The /dev/shm filesystem (symlinked to /run/shm on some Linux distributions) is a tmpfs filesystem used to hold shared memory objects. Kognitio uses these objects to hold memory images. Typically this filesystem is mounted with a limit of 50% of system memory, which is not enough to run a Kognitio cluster in a container that uses most of a node’s memory. You will typically need to remount /dev/shm with the option ‘size=90%’ to allow up to 90% of system memory to be used for shared memory objects. For a running node you can do this with:

This will take effect immediately but will not persist after a reboot. To persist the change after a reboot, make this change in /etc/fstab, for example:

tmpfs                   /dev/shm                tmpfs   size=90%        0 0