You can use CPU DR to decrease the number of the control domain's cores from an initial factory-default configuration. However, you must use a delayed reconfiguration instead of a memory DR to decrease the control domain's memory.
When in the factory-default configuration, the control domain owns all of the host system's memory. The memory DR feature is not well suited for this purpose because an active domain is not guaranteed to add or, more typically, give up, all of the requested memory. Rather, the OS running in that domain makes a best effort to fulfill the request. In addition, memory removal can be a long-running operation. These issues are amplified when large memory operations are involved, as is the case for the initial decrease of the control domain's memory.
This procedure shows how to decrease the CPU and memory resources from the control domain's initial factory-default configuration. You first use CPU DR to decrease the number of cores and then initiate a delayed reconfiguration before you decrease the amount of memory.
The example values are for CPU and memory sizes for a small control domain that has enough resources to run the ldmd daemon and to perform migrations. However, if you want to use the control domain for additional purposes, you can assign a larger number of cores and more memory to the control domain as needed.