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Oracle® VM Server User's Guide Release 2.1 Part Number E10898-04 |
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# D Oracle VM Agent Architecture

This Appendix contains more detailed information on the architecture and deployment options for the Oracle VM Agent. It contains:

- Oracle VM Agent Architecture

- Oracle VM Agent Deployment

## D.1 Oracle VM Agent Architecture

Oracle VM Agent is installed with Oracle VM Server. Oracle VM Manager manages the virtual machines running on Oracle VM Server through the Oracle VM Agent. Three types of agents are implemented:

- Server Pool Master: This acts as the contact point to the outside world of Oracle VM Server and dispatches to other Oracle VM Agents. It also provides virtual machine host load-balance, and local persistency of Oracle VM Server information.

- Utility Server: This mainly focuses on creating, removing, migrating, and so on of I/O intensive operations.

- Virtual Machine Server: The virtual machine server. This is the daemon for Oracle VM Server virtual machines. Virtual Machine Server can start and stop virtual guests. It also collects performance data for the host and guest operating systems. Acts as a hypervisor for domUs.

Figure D-1 Oracle VM Agent

Description of "Figure D-1 Oracle VM Agent"

## D.2 Oracle VM Agent Deployment

Oracle VM's deployment architecture utilizes server pools, with shared access to storage across Oracle VM Servers in the server pool. Guest virtual machines are stored on the shared storage and placed on one of the Oracle VM Servers in one of two ways to balance the workloads of the server pool:

- Auto: Selects the Oracle VM Server in the pool with most available resources (for example, memory) to start the guest virtual machine.

- Manual: Allows the user to designate a pool of Oracle VM Servers as preferred servers where the guest virtual machine is allowed to start and run.

Since the guest virtual machines are not bound to any specific physical Oracle VM Server in the server pool, unless preferred servers are explicitly specified in Oracle VM Manager, guest virtual machines are not prevented from powering-on simply because an individual Oracle VM Server happens to be down for maintenance or otherwise unavailable at the time. Further, since the load-balancing algorithm assures that a guest virtual machine is placed on the Oracle VM Server with the most resources available, it also helps assure the maximum aggregate performance from the server pool.

Oracle VM Manager communicates with Oracle VM Agent to perform the management of guest virtual machines and Oracle VM Servers in server pools. There are a number of configuration options you can use when deploying Oracle VM.

- The Server Pool Master, Utility Server and Virtual Machine Server can be on the same computer.

- The Server Pool Master and Utility Server can be on the same computer, and the Virtual Machine Server can be on another computer.

- All three Oracle VM Server agent components can be on separate computers.

Figure D-2, "Oracle VM deployment" shows the deployment options for managing Oracle VM Servers.

Figure D-2 Oracle VM deployment

Description of "Figure D-2 Oracle VM deployment"

A server pool consists of one or more physical Oracle VM Servers, and represents a logical view of the storage where the guests reside.

In Figure D-2, "Oracle VM deployment", Server Pool 3 is deployed on individual Oracle VM Servers, while in Server Pool 1, all of the three agents are deployed on a single Oracle VM Server. Server Pool 2 shows a more typical deployment. The Server Pool Master and Utility Server are on one computer, and the Virtual Machine Server(s) are on another, or multiple other computers. This improves overall performance as guests running on the Virtual Machine Server(s) may consume a large proportion of resources, and dedicated computers are often set aside for this.

In medium- to large-scale environments with more than just a few guests in a server pool, it is recommended that the Server Pool Master and Utility Server functions reside together, or individually, on a separate and dedicated Oracle VM Server that does not host any guests, as illustrated in Server Pool 3. This is to prevent any significant Server Pool Master and Utility Server usage from impacting the performance of the workloads hosted in the guests.

The storage in Figure D-2, "Oracle VM deployment" is a mounted file system dedicated to the server pool, and stores the guests, external resources and other data files shared by Oracle VM Servers on the server pool.

The decision on how to deploy Oracle VM Agent components is made using Oracle VM Manager. You cannot configure this using Oracle VM Server. You can set up Oracle VM Manager to manage your virtual machines, in any of the configurations in Figure D-2, "Oracle VM deployment". See the Oracle VM Manager User's Guide for information on setting up the management of virtual machines and server pools.