Increase the size of tmpfs with the following command:

sudo mount -o remount,size=2G,noatime /tmp

The previous size was 512 MB, now it’s 2 GB.

Note that these settings are reset when you reboot the machine.

👉 Source

Why

Manjaro uses tmpfs. tmpfs is a temporary filesystem that resides in RAM or SWAP because it is faster and ensure that the information will remove on reboot.

tmpfs is commonly used in directories like /tmp, /var/lock and /var/run.

By default, a tmpfs partition has its maximum size set to half of the available RAM

👉 Arch Linux Wiki

👉 Right size for the /tmp and how to change size? (Manjaro Forum)