When the database is down, no transactions occur. But as long as the storage medium (SSD, Spinning disks, PVC, whatever) - doesn't go down - then when the data

When the database is down, no transactions occur. But as long as the storage medium (SSD, Spinning disks, PVC, whatever) - doesn't go down - then when the database comes back up - anything that needs to be rolled back is rolled back, and things just keep running along without any problem. So - the user will see a "Pause" when using the application if the database is down - but that's it. The great thing about architecting your application stack in such a way that every one of the servers/applications/databases can disappear in a moments notice, is that your application becomes super robust to hardware failure - because having a sever go "down" is Business As Usual in Kubernetes.