2.16.2 Reducing Database Server Power Consumption by Setting a Power Consumption Target

Starting with the Oracle Exadata X11M system family and Oracle Exadata System Software release 25.1.0, you can specify a power consumption target for each database server.

Using this capability, you can limit database server power consumption to fulfill regulatory requirements, control cooling requirements, or meet environmental targets.

Note that limiting the server power consumption also constrains the peak server processing capacity. When processing demands are lower than the processing capacity available under the power consumption target, limiting power consumption does not affect performance. However, system performance is impacted when the workload requires more processing capacity than is available under the power consumption target. Typically, there is a good correlation between power consumption and server processing capacity. For example, if you reduce power consumption by 10%, you should expect a similar reduction in peak processing capacity.

The cpuTargetWattsMaxValue attribute defines the server's expected maximum power consumption (in Watts).

For example, on each 2-socket Oracle Exadata X11M database server with 192 CPU cores, cpuTargetWattsMaxValue=800. And, on a single-socket Oracle Exadata X11M-Z database server with 32 CPU cores, cpuTargetWattsMaxValue=240.

You can view the prescribed value for each server by listing the attribute value. For example:

DBMCLI> LIST DBSERVER attributes cpuTargetWattsMaxValue

The cpuTargetWatts attribute controls the power consumption target for the server. By default, the power consumption target is disabled and the cpuTargetWatts attribute contains no value. To specify a database server power consumption target, you can set the cpuTargetWatts attribute. For example:

DBMCLI> ALTER DBSERVER cpuTargetWatts=720

When setting the cpuTargetWatts attribute, permitted values are between 50% and 100% of the server cpuTargetWattsMaxValue value in increments of 20 Watts for each server CPU socket.

For example, on a 2-socket X11M database server with 192 CPU cores, where cpuTargetWattsMaxValue=800, you can set the cpuTargetWatts attribute to 400, 440, 480, and so on up to 800. And, on a single-socket X11M-Z database server with 32 CPU cores, where the cpuTargetWattsMaxValue=240, you can set the cpuTargetWatts attribute to 120, 140, 160, and so on up to 240.

You can also disable the power consumption target by resetting the cpuTargetWatts attribute to NULL or to an empty string ("").

At any time, you can view the current power consumption target by listing the attribute value. For example:

DBMCLI> LIST DBSERVER attributes cpuTargetWatts