Managing load and reducing power consumption are two of the major benefits of virtualization. When a server is already under significant load, it is preferable to distribute the virtual machines that it is running across less utilized servers within the server pool. Equally, during periods of low utilization it is preferable to consolidate virtual machines across as few servers as possible so that unused servers can be powered off to reduce energy consumption.
Oracle VM provides a facility to handle this kind of behavior automatically. This facility is handled by creating a server pool policy. Server pool policies allow you to define the different options that you wish to support. These are defined as follows:
Distributed Resource Scheduling: Used to optimize resource utilization through a form of load balancing. See Section 6.11.1, “Distributed Resource Scheduler (DRS)” for more information.
Distributed Power Management: Used to reduce energy consumption by consolidating virtual machines across fewer servers. See Section 6.11.2, “Distributed Power Management (DPM)” for more information.
It is also possible to apply these policies to the networks that are available within a server pool, by setting network utilization thresholds that trigger these behaviors within the server pool. This is discussed in more detail in Section 6.11.3, “DRS/DPM Network Policies”.
If you have set the inbound migration lock feature to disallow new virtual machines on an Oracle VM Server, then any server pool policies you set are restricted from migrating virtual machines, or creating new ones on the server. See Section 7.11, “How Can I Protect Virtual Machines?” for more information on using the inbound migration lock feature.