I wonder if Linux can mimic the technique Microsoft uses to grow volumes and filesystems on the fly. It's something I've missed on the occasion. It's pretty slick.
All my VMs have a separate /boot and ext4 as / (xfs would work, too).
With this setup - using KVM, mind you - I can change the disk size of the VM and resize the / filesystem inside by just using resize2fs, no need to reboot, umount or anything else.