Q:

Magento 2.2.2 - Warning: SessionHandler::read() No space left on device

My application is showing error:
Magento 2.2.2 - Warning: SessionHandler::read() No space left on device (28) in /var/www/html/vendor/magento/framework/Session/SaveHandler/Native.php on line 22

I searched for information and many of them said it was lacking server space, but my server has 3GB of space.

Memory and CPU usage information also appears to be normal

But when I execute:
bin/magento cache:clear

everything returns to normal and my application works again.
Magento is running on an AWS EC2 T2.Medium 16GB disk drive and 4GB RAM.
Folders and files are set according to Magento documentation:
sudo find var generated vendor pub/static pub/media app/etc -type f -exec chmod g+w {} + && sudo find var generated vendor pub/static pub/media app/etc -type d -exec chmod g+ws {} + && sudo chown -R :apache . && sudo chmod u+x bin/magento

A:

This is a storage issue, as per my earlier suggestion. recommendation for this is/was to update storage from 16gb to 20gb if anyone else has this issue i suggest this is the first place you look .
Why this happen even after space on the server:
when your server performs certain tasks it used additional space to run processes in the background it may only use them temporarily but going off your error so the server does not have enough space to run its tasks.

