Re: [atomic-devel] Proposal for default qcow2 image virtual size 10G instead of 6G

[Colin Walters <walters verbum org>]

On Fri, Sep 4, 2015, at 12:50 PM, Vivek Goyal wrote:

> Virtual size of qcow2 f22 atomic size is 6G. 

This comes from https://pagure.io/releng/blob/master/f/scripts/build-cloud-images#_93

Now, one important thing about the cloud image is that via cloud-init it supports dynamic extension of the drive.  The primary use case is in IaaS - OpenStack, AWS etc.  These systems will typically let you choose at boot time to use 10G, 20G, 160G or whatever you want, and growpart/cloud-init will extend the drive.  docker-storage-setup then kicks in and balances things between the host and Docker.

If you're booting the cloud image in bare libvirt...welll, this type of thing
is better covered by Vagrant.  (And the Vagrant box is 40G, for this reason):
https://pagure.io/releng/blob/master/f/scripts/build-cloud-images#_114

If you still want to use raw libvirt, I have a really stupid script here:

https://github.com/cgwalters/homegit/blob/master/bin/walters-create-cloud-vm

which shows how to create a CoW image with any size you choose.

> Is it a good idea to bump up default virtual size to 10G?

So per above, I'd say Vagrant is going to be more ergonomic for users
who hit this problem. That said I'm not opposed to increasing to 10G,
in the end it's all thinly provisioned.