[geggo98]

In the Cassandra case, you would not write the persistent data in the Docker image (that's the part of the file system mounted as a layered file system, using AUFS or OverlayFS). Instead, you would write it in a volume. For a local volume, that's just a part of the "normal" file system (Ext4, XFS, ...) exposed to the Docker container through a bind mount.

Volumes are quite stable and reliable when based on a stable file system.

So while you could lose the container due to the but describe, you would not lose the persistent data.

It's best practice not to write to the Docker image at all during runtime (no log files, no PID file, etc), but to write only to volumes or tmpfs mounts. I'm a little bit suspicious about the crashes you described: are you sure you followed that best practice?