Ephemeral Storage

[snap0]

Is it possible to have large ephemeral disk?

[greg]

Based on this thread, it should be already. But …

Scaling Ephemeral Disk

It’s not! We actually don’t intend for the ephemeral disk space to be written to. It’s writable just because so much stuff breaks without it, but we’d make it readonly if we could. You can use autoscaling with persistent volumes, though, so that’s worth a try. We’ll have a better way to autoscale with disks in a few months.

Given that, I’d recommend deciding how much space you need, create a volume of that size, and then mount that volume to the app. Gives you complete control over it:

Fly Volumes overview