Oracle VM Server – Memory Size of the Management Domain (Dom0)

Oracle VM Server installer using the below algorithm to set default memory size for dom0:

dom0 Memory = 502 (MB) + (Physical Memory (MB) * 0.0205)

As an example, your physical server has 256 GB memory, dom0 needs to 5.7 GB memory.

If you didn’t assign enough memory to dom0, you will face with serious performance issues.

So calculating dom0 memory is very important for preventing performance issues on your virtual machines.

Also you can change dom0 memory size by the below instruction:

Edit your grub configuration on the Oracle VM Server to adjust the value for the dom0_mem parameter. If you are using UEFI boot, the grub configuration file is located at /boot/efi/EFI/redhat/grub.cfg, otherwise the grub configuration file is located at /boot/grub2/grub.cfg. Edit the line starting with multiboot2 /xen.gz and append the required boot parameters. For example, to change the memory allocation to 1024 MB, edit the file to contain:

multiboot2 /xen.gz dom0_mem=max:1024M placeholder ${xen_rm_opts}