resize or migrate problem

hello I use OpenStack and I create some VMs in different compute in one region. when I resize the VM. if the compute doesn't have enough space, automatically the vm will be migrated to another compute. but my problem is here that when it migrated, the _base file doesn't migrate and remains in the first compute that it doesn't have enough space. because of this, the VM appears with an error status in OpenStack. if I move the _base from first compute to final compute and reboot the server this problem has been solved. so i need to not transfer _base manually and if it migrated to another compute the disk and _base transfer with each other. could you please help me to solve this problem? thanks in advance