Amazon Linux 2022 Tempfs

Things to know when migrating from Amazon Linux 1 or Amazon Linux 2 to Amazon Linux 2022 - tempfs

Amazon Linux 2022 comes equipped with /tmp directory mounted in memory. It’s visible in df as a separate device

/dev/xvda1      8.0G  4.2G  3.9G  52% /
tmpfs           986M     0  986M   0% /tmp

Rather than a fixed entry in /etc/fstab, it uses a service to remount the /tmp after a reboot



Tempfs is fast. Absurdly fast for something that looks like ‘a storage’. The service definition mentioned above automatically allocates 50% of RAM as possible storage.


If your software depends on a large volume of temporary files, you have to carefully measure the performance - if you fill in the /tmp with your files, and the demand for RAM from application raises, system will start using swap and that will obviously have a massive impact on performance

How to disable it

As mentioned earlier, it’s mounted after each reboot via a service, so it is as simple as stopping the service and then disabling it.

sudo systemctl disable tmp.mount
sudo systemctl stop tmp.mount

But now the /tmp is useless, so let’s recreate it.

sudo rm -rf /tmp
sudo mkdir /tmp
sudo chmod 1777 /tmp

test: df -h should show you no /tmp as a separate mountpoint.