7.4 Configuring the System Software to Use Additional Memory

Caution

This section applies only to systems running software release 2.0.5 or earlier.

The Oracle PCA Release 2.3 software automatically reconfigures the system software when changes in RAM are detected. You no longer need to execute the procedures in this section. If the instructions in this section were applied to a system with a previous software release, those changes are overwritten when the node reboots after the software upgrade.

Once the memory upgrade is installed you must apply specific configuration changes to make optimal use of the additional RAM and ensure correct provisioning functionality. The following changes are required:

reconfiguring the bootloader (GRUB) on the compute node with the memory upgrade
updating the PXE template for compute node (re-)provisioning

Reconfiguring GRUB on a Compute Node with Memory Extension

Warning

This configuration change is not persistent in the current Oracle PCA release. Reprovisioning the compute node results in the changes being overwritten, so you will be required to execute the same procedure afterwards.

Start the compute node after RAM installation.
Using SSH and an account with superuser privileges, log into the compute node.

Edit the file /etc/grub.conf and change the dom0_mem value from the default 5888M to the correct amount of RAM installed. The entries are highlighted in the example below.

Note

If the total amount of RAM is now 512GB, set dom0 memory to 11264M.

If the total amount of RAM is now 768GB, set dom0 memory to 16512M.

root@ovcacn07r1 ~]# cat /etc/grub.conf
# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE:  You have a /boot partition.  This means that
#          all kernel and initrd paths are relative to /boot/, eg.
#          root (hd0,0)
#          kernel /vmlinuz-version ro root=/dev/sda2
#          initrd /initrd-version.img
#boot=/dev/sda
default=0
timeout=5
title Oracle VM Server (2.6.39-400.249.3.el5uek)
        root (hd0,0)
        kernel /xen.gz console=com1,vga com1=9600,8n1 dom0_mem=5888M dom0_vcpus_pin dom0_max_vcpus=16 allowsuperpage  crashkernel=256M@64M
        module /vmlinuz-2.6.39-400.249.3.el5uek ro root=UUID=f8b8e26c-532a-464f-ad0a-f535f8b70cea  console=hvc0 console=tty0 console=xvc0 swiotlb=131072
        module /initrd-2.6.39-400.249.3.el5uek.img
title Oracle VM Server-ovs (xen-4.1.3 2.6.39-300.32.5.el5uek)
        root (hd0,0)
        kernel /xen.gz dom0_mem=5888M dom0_vcpus_pin dom0_max_vcpus=16 allowsuperpage  crashkernel=256M@64M
        module /vmlinuz-2.6.39-300.32.5.el5uek ro root=UUID=f8b8e26c-532a-464f-ad0a-f535f8b70cea console=tty0 console=xvc0 swiotlb=131072
        module /initrd-2.6.39-300.32.5.el5uek.img
title Oracle VM Server-ovs serial console (xen-4.1.3 2.6.39-300.32.5.el5uek)
        root (hd0,0)
        kernel /xen.gz console=com1,vga com1=9600,8n1 dom0_mem=5888M dom0_vcpus_pin dom0_max_vcpus=16 allowsuperpage  crashkernel=256M@64M
        module /vmlinuz-2.6.39-300.32.5.el5uek ro root=UUID=f8b8e26c-532a-464f-ad0a-f535f8b70cea  console=hvc0 console=tty0 console=xvc0 swiotlb=131072
        module /initrd-2.6.39-300.32.5.el5uek.img

Save the changes to grub.conf and reboot the compute node to allow these changes to take effect.
If you installed memory extension kits in multiple compute nodes, repeat these steps on each of those nodes.

Editing the PXE Template for Compute Node Provisioning

Warning

This configuration change is not persistent in the current Oracle PCA release. An update of the appliance controller software will overwrite the change, so you will be required to execute the same procedure afterwards.

Using SSH and an account with superuser privileges, log into the active management node.

Edit the file pxelinux_cfg_OVM_template located on the shared storage and make sure the APPEND line contains dom0_mem=5888M as highlighted in the example below.

[root@ovcamn05r1 ~]# cat /nfs/shared_storage/pxe_templates/pxelinux_cfg_OVM_template
default OVCA-COMPUTE-OVM-1
LABEL OVCA-COMPUTE-OVM-1
        KERNEL OVM/mboot.c32
        APPEND OVM/xen.gz dom0_mem=5888M --- OVM/vmlinuz ks=nfs:XXXNFS_IPXXX:/export/MGMT_ROOT/kickstart/XXXKICKSTART_FILEXXX \
        ksdevice=eth0 linksleep=50 --- OVM/initrd.img

This value works for all supported RAM configurations. Compute node (re)provisioning will function as expected.