Thursday, June 4, 2015

EXADATA -- 1/8 Processor resourcecontrol, UEFIBIOS and ubiosconfig

The limits in Exadata are forced by BIOS and controlled by "resourcecontrol" utility present in the servers.
To five an example of the usage, we can say that , in the case of compute nodes, resourcecontrol utility updates the BIOS and disables the half of the CPU cores.
It seems a command like "/opt/oracle.SupportTools/resourcecontrol -core desiredcorenumber" followed by a reboot does the job.
In other words, the resourcecontrol utility is used to configure the core count on Oracle Exadata Database Machine, so it is an interface between OS and the BIOS.

The following example shows the syntax for the utility:

resourceControl -capacity_on_demand \
{display | disable | enable} [-cores number_of_cores] [-force]
The following table describes the parameters used with the resourceControl utility.
Parameter Description
display Displays the number of CPUs in use.
disable Disables the CPUs reserved for additional on-demand capacity. At least two CPUs must be enabled at all times.

enable Enables the CPUs reserved for additional on-demand capacity.
-cores Sets the number of CPUs to enable or disable.
-force Forces the enabling or disabling of the CPUs.

In my reseaches, I have found HP servers have the specific BIOS option for disabling cores.. It is an option in BIOS menu where one can define the maximum numbers cpu core per socket. However, I could not find any similar BIOS menu option for SUN/Oracle Servers..

It seems resourcecontrol script do this from the backend.

Actually, the resourcontrol uses ubiosconfig tool for this job.. ubiosconfig is found on the latest Oracle servers, which enables the configurations of UEFI BIOS. It is a tool considered within the Oracle Server CLI Tools.

During this process, the settings stored in an xml file are imported by ubiosconfig .. The operation is done in expert mode (--expert_mode), which is not documented as far as I see:) , but I guess it is a secret flag that must used for such expert operations. (like the fdisk's expert mode)

Handling the BIOS from the Operating System is pretty interestring, that 's why shared this with you.

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