not that I'm aware of. If you don't have memory hotadd enabled, then the VM has to be shut down to change the RAM configuration.
Can you try manually in vSphere web client?
What's the exact error message?
Reservation should not stop you to allocate more RAM, even if you are over committing it.
Share the error msg.
as my server is production one, I am not able to provide today error, but here is error msg from my try over Orchestrator:
An unexpected error was received from the ESX host while powering on VM vm-36204.
Module MemSched power on failed.
An error occurred while parsing scheduler-specific configuration parameters.
Invalid memory setting for FPT: memory reservation (sched.mem.min) should be equal to memsize(8192)
HA must be enabled in ur environment and unmanaged stot size is not letting power ON VM. This is the major consideration while applying Reservation.
we solve this for our env, so I mark this as answered, thanks for all your answers