Introduction

SquashFS

In order to put a JVM in a RAM disk we are going to use the tool SquashFS.

Use the following command to install the Squash FS tools.

sudo apt-get update
sudo apt-get install squashfs-tools

Make a squashfs file out of your desired JVM:

cd /usr/lib/jvm
sudo mkdir ramdisk
mksquashfs /usr/lib/jvm/java-8-oracle /usr/lib/jvm/ramdisk/java-1.8.0.91-oracle.sqsh

At this point you have an existing JVM squashed in .sqsh file.

Create a mountpoint for the ramdisk:

sudo mkdir /media/ramdisk-java-8-oracle

Edit your /etc/fstab and define your mount point as a tmpfs by adding the following declaration:

# change the default size for the ramdisk
tmpfs /media/ramdisk-java-8-oracle tmpfs defaults,size=400M,mode=1777 0 0