+1 on increasing the default demo VBox disk size!
Maybe 50GB would be enough, but 10G is clearly too small. I just tested the upgrade from 18.03 to 18.09beta in a demo VM and I had to nix-collect-garbage -d and nix-store --optimise to be able to nixos-rebuild in 18.09. And still I was left with 93% used space on / after the upgrade.

There is no drawback for having a larger virtual disk, the on-disk size does not increase noticeably.

Ah, I missed the ongoing discussion here before filing #48149

It looks like 100GB is indeed untenable with the default timeouts. We can try some changes to the timeouts and a slightly smaller size, but it looks like the increase in time is not linear with the size increase, but way worse.

(I also missed that the purpose was indeed to bump the demo image size, making the PR less ideal, but we do need to unblock the channel asap.)

Reverted to get out of troubles first.

Now: I'm not sure I understood why the build took much longer yet.
But yes the initial goal was to extend the volume of the official demo VM so that users get more free space out of the box.

Well, that's sad. I'll try to reproduce the timing issue, maybe submit another PR.
Thanks!

I wonder if there might be a way to ship a VBox OVA with a native VDI disk... At least it would be easier to extend it afterwards.

@obadz I think I understand the motivation behind commit 80660f8 but what do you think would be the consequences now of converting the raw disk to VDI given that the raw disk is later deleted?

Or to put it in code :

echo "creating VirtualBox pass-through disk wrapper (no copying invovled)..."
VBoxManage convertfromraw $diskImage disk.vdi --format VDI
[...]
rm -v $diskImage

Using the native commands of VBox.

You can set max-silent-time to reproduce this. For instance:

nix-build -A ova '<nixpkgs/nixos/release.nix>' --option max-silent-time 7200

It actually looks like it is able to make the .vdmk file. It just fails somewhere else down the line. Perhaps there's a verbose option to one of these commands that will solve it?

Is resizing an image really such a pain?

VBoxManage modifyhd X.vdi --resize Y

But we don't use a VDI or VHD image by default and VBox can only resize those.
Since NixOS OVA ships with a raw disk wrapped inside a VMDK container then one would first need to convert the disk... And that is a pain.

But #49317 pushed the VM disk to a max of 50GB without changing anything to the disk format so we found a middle ground solution to this problem.

Thanks for replying, still.

Sounds good. Sorry for delay.