You can use the memory DR feature to reconfigure the memory of the control domain. If a memory DR request cannot be performed on the control domain, you must first initiate a delayed reconfiguration.
Using memory DR might not be appropriate for removing large amounts of memory from an active domain because memory DR operations might be long running. In particular, during the initial configuration of the system, you should use delayed reconfiguration to decrease the memory in the control domain.
Use a delayed reconfiguration instead of a memory DR to decrease the control domain's memory from an initial factory default configuration. In such a case, 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.
For these reasons, use a delayed reconfiguration by following these steps:
Use the ldm start-reconf primary command to put the control domain in delayed reconfiguration mode.
Partition the host system's resources that are owned by the control domain, as necessary.
Use the ldm cancel-reconf command to undo the operations in Step 2, if necessary, and start over.
Reboot the control domain to make the reconfiguration changes take effect.