Creating a Linux RAM disk (tmpfs)

This post explains how to use a RAM disk (tmpfs) on Linux.

Use it carefully because the contents of the RAM disk are deleted when the device powers off.

Check available RAM

Check the system’s free RAM.

$ free --mega
              total        used        free      shared  buff/cache   available
Mem:           8071        2426        4778          85         867        5314
Swap:             0           0           0

The available column shows that 5314 MB is available.
I will use 3 GB of it.

Create and mount the mount point

Create the directory to use as the RAM disk mount point.

$ sudo mkdir /mnt/ramdisk

Mount the RAM disk.

$ sudo mount -t tmpfs -o size=3G tmpfs /mnt/ramdisk

You can check the mounted RAM disk with the following command.

$ df -h
Filesystem      Size  Used Avail Use% Mounted on
...
tmpfs           3.0G     0  3.0G   0% /mnt/ramdisk

Configure /etc/fstab

Configure the RAM disk to be mounted automatically on boot.

Edit /etc/fstab with the following command.

$ sudo nano /etc/fstab

Add the following line to /etc/fstab.

tmpfs /mnt/ramdisk tmpfs defaults,size=3G 0 0

From now on, the RAM disk will be mounted automatically on each boot.

Extra: Unmount and remove the RAM disk

This explains how to unmount and remove the RAM disk.

Use the following commands to delete the RAM disk contents and unmount it.

$ sudo rm -rf /mnt/ramdisk/*
$ sudo umount /mnt/ramdisk

Remove the line added to /etc/fstab.

$ sudo nano /etc/fstab

Remove the mount point.

$ sudo rmdir /mnt/ramdisk