Storage: instance size vs. block storage



Hi! I’ve just signed up for the free trial and am playing around. I’ve got an instance up and running, which says that it has 80GB in its primary partition. I haven’t yet set up a volume, and it appears that I haven’t used any of the 25GB block storage that I have available in the free trial account.

My confusion is regarding the difference if any between the storage that the instance has available, and the storage that my free trial account has available.

Is the 80GB in the instance in addition to any volumes that I create? Is it somehow limited by the 25GB storage I have available? Is there a reason why I should create a volume and use that instead of the 80GB that the instance has?

Basically… it looks like I’ve got 80GB of storage available in my instance, but I haven’t used any of the 25GB block storage that is included in my account.

Selecting Volume Size When Creating Instance From Pre-configured Image

The reason for this is that you’ve launched an ephemeral instance and ephemeral storage doesn’t count against your block storage usage.

An ephemeral instance means that everything involved with the instance is temporary, including the hard drive. When you terminate the instance, it’s gone forever.

When you boot an instance from a volume or create a volume, that volume can stick around even after you’ve terminated the instance it’s connected to. That allows you to keep data on that volume and use it later. Think of it like an external USB drive for all your DreamCompute instances.

Only when you create a volume (i.e. hard drive), does that count against your block storage allowance.

Hopefully that clarifies things a bit!


Ok, got it.

If I don’t personally intentionally terminate the instance, are there other circumstances in which that 80GB of configured OS and/or data would be lost?


Yes, if the underlying hypervisor needed to be rebooted for any reason (i.e. security patches) there is the chance the ephemeral instance will be destroyed. The short version is that if you value the data, keep it on a persistent volume!


I think I’m getting it, but correct me if I’m wrong here: It seems that running an instance off ephemeral storage is mainly useful if you’ve got a custom image set up so that you can re-create it quickly (or spin up another one if you need multiple instances based on the same image). There’s little point creating an instance on ephemeral storage based on a standard OS install image, then putting a lot of time into configuring it, and installing software on it, if it can be lost at any time. (It makes perfect sense for testing new software and configurations, of course.)

(The main thing I’m learning here is how much of a newbie I am to all this!)

Will there be a way to create an image from an instance?


You can create a new instance from a snapshot of a volume. You can also create an instance from a snapshot of an ephemeral instance. (Different options in the create instance pop-up.)