Does KVM support thin provision - i.e. if we assign a VM a virtual disk size of 100 GB - it does not allocate 100 GB right away rather allocates the space used and expands the vd as needed. Also - if it is supported - how do we accomplish this via cloudmin / webmin?
KVM supports it, as long as you pick the right file format. QCOW2, for example.
I've never used Cloudmin, so I'm afraid I can't help you there...