I deployed a vm with 10 GB QSFS storage using the terraform example in the manual. Curious as to see what happens when all the space is used up, I decided to store 20GB of random data in there. In the end I was unable to access the mounting point because the socket was not connected. My shell history should tell the tale as well:
vm1:/store# df -h
Filesystem Size Used Available Use% Mounted on
dev 480.5M 0 480.5M 0% /dev
run 486.2M 4.0K 486.2M 0% /run
tmpfs 486.2M 0 486.2M 0% /dev/shm
/dev/root 1.7T 3.7M 1.7T 0% /
2758446qsfs 10.0G 1.0K 10.0G 0% /store
vm1:/store# head -c 20401094656 /dev/urandom > myfile
vm1:/store# ls
ls: .: Socket not connected