If you have upgraded from an earlier release, it is possible
that some of the hypervisor boot parameters for your server
may need editing to ensure that newer features are enabled. To
update these boot parameters, on each affected Oracle VM Server, open
/boot/grub.conf
in an editor. Edit the
line starting with kernel /xen.gz
and append the
required boot parameters.
To support Huge Pages on Para-Virtualized (PV) guests
Huge page support, for PV guests, requires that the Xen
hypervisor starts with the boot parameter
allowsuperpage
set. To allow the hypervisor
to use this feature when starting up virtual machines, you
must append the option to the kernel boot parameters. For
example:
kernel /xen.gz console=com1,vga com1=57600,8n1 dom0_mem=1440M allowsuperpage
You must reboot the server for this setting to take effect.
For large servers with more than 20 physical CPUs
For Oracle VM Servers with more than 20 physical CPUs, performance can
be improved by pinning virtual CPUs to dom0 and setting a
maximum value for the number of virtual CPUs that can be used
by dom0. On a new install where a system has more than 20
physical CPUs, this value is usually set to 20. To ensure that
you get the best possible performance on an Oracle VM Servers with
more than 20 physical CPUs, set the Xen boot parameters
dom0_vcpus_pin
and
dom0_max_vcpus=20
. For example:
kernel /xen.gz console=com1,vga com1=57600,8n1 dom0_mem=32768M allowsuperpage dom0_vcpus_pin \ dom0_max_vcpus=20
You must reboot the server for these settings to take effect.