The question is what happens if the disk that host the In-Memory checkpoint files runs out of disk space? So I decided to do some testing and document the symptoms and recovery steps here in case you run into such issue. With our Azure, test was really easy. All I had to do was to spawn a VM and attach a very small disk to simulate out of disk space condition.
If your disk runs out of space, you will see various errors below though your database stays online
It looks like you can work your way out of a full drive scenario. Hopefully, however, you won’t get into this scenario too often.