since you mentioned that you do not want to partition the volume, an alternative approach could involve creating a disk quota at the operating system level. Disk quotas are a feature provided by the operating system (in this case, the Hyper-V host) that allows you to set limits on the amount of disk space a specific user or group can consume.
Set up the network share on the Hyper-V host where you will store the FOG images. Ensure the share is accessible from the FOG VM. Inside the FOG VM, mount the network share to the /images directory, which is where FOG stores the images. You can do this using the mount command or by adding an entry in /etc/fstab for persistent mounting. Configure disk quotas on the Hyper-V host for the user or group associated with the FOG VM. Set the quota limit to the desired amount of disk space you want FOG to use for images.
Keep in mind that disk quotas are managed at the operating system level and are not specific to FOG. Therefore, this method will not provide real-time monitoring of disk usage within the FOG web interface. You will need to monitor the disk space usage separately on the Hyper-V host.