Storages that do not have a backing device (such as ephemeral) need to be handled properly at the sandbox level. There are few suggestions by @bergwolf and @WeiZhang555 that need to be sorted out.
We can use this issue as a placeholder to keep the discussion public.

Requesting @bergwolf and @WeiZhang555 and whoever else is interested to put their thoughts here so that a larger community can participate.

The result of this discussion will lead to refactoring the support for ephemeral PR