admin server

An Oracle VM Server dedicated to performing administrative functions on storage servers such as creating a new LUN or extending a file system. The server must be capable of logging into a storage array or file server as an admin user. The administrative functions available to the server are defined by the Oracle VM Storage Connect plug-in.


Specify that specific virtual machines should never run on the same host.



Bonding is a Linux OS feature that provides a method for aggregating several ports into a single bonded interface, to provide load balancing or redundancy. When you discover an Oracle VM Server, the bonded interface is shown as containing a single port.

Network bonding refers to the combination of network interfaces on one host for redundancy and/or increased throughput. Redundancy is the key factor: You want to protect your virtualized environment from loss of service due to failure of a single physical link.

In Oracle VM, there are three modes of network bonding:

  • Active - Backup: One Network Interface Card (NIC) is active while the other NIC is standby. If the active NIC goes down, the other NIC becomes active.

  • Dynamic Link Aggregation: All NICs act as one NIC and the network traffic flows through all interfaces concurrently, which results in a higher throughput. With this mode, your network administrator must create LACP (Link Aggregation Control Protocol) bonding on the network switch(es).

  • Load Balanced: The network traffic is equally balanced over the NICs of the bond. This mode does not require any special configuration on connected network switch(es), However, this mode does not support using VLAN with bridges. If using this mode for your bonded interfaces in any network, you cannot use VLANs if this network is configured with the Virtual Machine network channel.



The action or result of making an exact copy of an object. The object may be a virtual machine, virtual machine template, ISO file, or virtual disk. Cloning is similar to copying and maintains the integrity of the original object, while creating a new object based on the original. A clone customizer may be used to define cloning options to specify details of where the object components may reside when cloned, such as in a different storage repository.

control domain

A privileged domain that creates and manages other logical domains and services. This term is often used in SPARC environments to refer to domains that behave like dom0. The control domain is named primary.

See Also: domain

See Also: dom0

See Also: domU


distributed power management

DPM complements DRS to reduce the Oracle VM Servers in a server pool when there are periods of low resource utilization. It can automatically add capacity as needed when resource utilization ramps up.

See Also: distributed resource scheduling

distributed resource scheduling

DRS provides real-time monitoring of Oracle VM Server utilization with the goal to rebalance a server pool to provide consistent resources to the running virtual machines. DRS migrates load away from heavily loaded Oracle VM Servers to less heavily loaded Oracle VM Servers.

See Also:distributed power management


An abbreviation for domain zero. The management domain with privileged access to the hardware and device drivers. Dom0 is the first domain started at boot time. Dom0 has more privileges than domU. It can access the hardware directly and can manage the device drivers for other domains. It can also start new domains.

See Also: control domain


An unprivileged domain with no direct access to the hardware or device drivers. Each domU is started by dom0.



Events are used to register status information of "objects" within Oracle VM Manager for future reference or to make problems easier to trace back. Events are often, though not always, related to jobs that are initiated within Oracle VM Manager. For instance, when a job fails, an event is generated. Events can also be triggered through changes in the environment such as server crashes or storage disconnects. Therefore, events are used to alert you to potential problems that may need your attention.

Events are categorized by severity. Most events will be informational, but they can also be warnings or errors. If an event has an error level severity, you need to acknowledge the error event to clear the error and to perform further operations on the object that generated the error.

See Also: jobs



Gibibyte (GiB) is a unit of digital information storage used to denote the size of data. One gibibyte is equal to 1024 mebibytes. Gibibyte is closely related to gigabyte, where one gigabyte is equal to 1000 megabytes.

GPG key

The GPG key (or GnuPG key) is the key used in the GNU project's implementation of the OpenPGP key management standard. The GPG key is used to check the validity of a YUM repository, and any packages (RPMs) downloaded from the repository.


hardware virtualized machine (HVM)

A hardware virtualized guest runs on the virtualization platform as it would on a physical host. Because the device drivers of the hardware virtualized guest are emulated, dom0 must contain device emulation code to support the guest’s device drivers. The other types of privileged instructions issued by the hardware virtualized guest, for example, for CPU or memory access, are not emulated, but are trapped, which also requires support from CPU vendors.

The guest’s OS does not require any modification to run as a hardware virtualized guest.

A virtual machine with an unmodified guest operating system. It is not recompiled for the virtual environment. There may be substantial performance penalties running as a hardware virtualized guest. Enables Microsoft Windows™™ operating system to be run, as well as legacy operating systems. Hardware virtualization is only available on Intel® VT or AMD SVM CPUs.

host computer

The physical computer on which the software is installed. Typically used to refer to either the computer on which Oracle VM Server or Oracle VM Manager is running.


HugePages is a feature integrated into the Linux kernel to support memory pages greater than the default. Using very large page sizes can improve system performance on a virtual machine by reducing the amount of system resources required to access page table entries.



Jobs consist of discrete operations that take place through Oracle VM Manager, such as server discovery, presenting a repository and creating a VM. Jobs are assigned a status that is refreshed according to their progress. A history of all jobs in the environment is stored within Oracle VM Manager.

Since jobs are oftened performed sequentially and sometimes take time to complete, tracking the status of a job allows you to understand what actions the system is currently performing, and which actions are queued to run in sequence after the current job has completed. Jobs also allow you to access system messages that may be useful to debug the failure of an operation.

Most jobs tend to generate events that each have a different severity level.

See Also: events


local storage

Local storage consists of hard disks installed locally in an Oracle VM Server. Local storage is often not appropriate for enterprise production environments, because it sharply constrains the ability of a virtual machine to run anywhere in the server pool in the event of the failure of the Oracle VM server, which owns the local storage, and because the management overhead of this storage is often significant.



The act of moving a virtual machine from one Oracle VM Server to another, or to the Unassigned Virtual Machines folder. Technically, a migration can only be performed on a running virtual machine, however the Oracle VM Manager Web Interface and Oracle VM Manager Command Line Interface may combine multiple operations to make it appear that you can perform a migration on either a running or a stopped virtual machine.


The act of moving an object from one location to another. This may be moving a stopped virtual machine from one Oracle VM Server to another, moving a virtual machine template from one storage repository to another, or moving an ISO file or virtual disk to another storage location. In the case where a live migration is performed on a virtual machine located on a local repository, the migration operation may move the virtual machine across repositories even though the virtual machine is running as part of the migration process.


The technique of creating more than one physical path between the server CPU and its storage devices. It results in better fault tolerance and performance enhancement. Oracle VM supports multipath I/O out of the box. Oracle VM Servers are installed with multipathing enabled because it is a requirement for SAN disks to be discovered by Oracle VM Manager


non-sparse copy

A clone of the type "non-sparse copy" is a disk image file of a physical disk, taking up the space equivalent to the full specified disk size, including empty blocks.

See Also: sparse copy



Oracle Cluster File System (OCFS2) is a general-purpose shared-disk cluster file system for Linux capable of providing both high performance and high availability. OCFS2 is developed by Oracle and is integrated within the mainstream Linux kernel. OCFS2 is used within Oracle VM to facilitate clustered server pools, storage of virtual machine images and for the purpose of allowing guests to share the same file system.

A clustered server pool always uses an OCFS2 file system to store the cluster configuration and to take advantage of OCFS2's heartbeat facility. There are two types of heartbeats used in OCFS2 to ensure high availability:

  • The disk heartbeat: all Oracle VM Servers in the cluster write a time stamp to the server pool file system device.

  • The network heartbeat: all Oracle VM Servers communicate through the network to signal to each other that every cluster member is alive.

These heartbeat functions exist directly within the kernel and are fundamental to the clustering functionality that Oracle VM offers for server pools. The server pool file system should be stored on a separate NFS server or on a small LUN if possible, as OCFS2's heartbeat facility can be disturbed by intensive I/O operations taking place on the same physical storage.

A storage repository configured on a LUN-based repository must be linked to a clustered server pool due to the nature of the OCFS2 file system. As a result, LUN-based repositories cannot be shared between multiple server pools, although it is possible to move an OCFS2 repository from one server pool to another.

For more information on OCFS2, please refer to

Oracle VM Agent

An application installed with Oracle VM Server. The Oracle VM Agent receives and processes management requests, and provides event notifications and configuration data to the Oracle VM Manager. Oracle VM Manager manages the virtual machines running on Oracle VM Server by communicating with Oracle VM Agent. It contains three components: master Oracle VM Server, Utility Server, and Virtual Machine Server.

Oracle VM Manager

Oracle VM Manager is the management platform, which offers an easy-to-use, web-browser interface as well as a command-line interface (CLI). Oracle VM Manager tracks and manages the resources available in your virtual environment and allows you to easily manage Oracle VM Server pools. Oracle VM Manager lets you manage the virtual machine life cycle, including creating virtual machines from templates or from installation media, deleting, powering off, uploading, deployment and live migration of virtual machines. Oracle VM Manager also lets you manage resources including ISO files, templates and shared virtual disks.

Oracle VM Server

A self-contained virtualization environment designed to provide a lightweight, secure, server-based platform for running virtual machines. The Oracle VM Server comprises a hypervisor and a privileged domain (called dom0) that allow multiple domains or guest operation systems (such as Linux, Solaris, and Windows) to run on one physical machine. Includes Oracle VM Agent to enable communication with Oracle VM Manager.

The Oracle VM Server for x86 incorporates an open source Xen hypervisor component, which has been customized and optimized to integrate into the larger, Oracle - developed virtualization server. The Oracle VM Server for x86 is also responsible for access and security management and generally acts as the server administrative entity, because the hypervisor’s role is limited.

On Oracle VM Server for SPARC systems, the SPARC hypervisor is built into the SPARC firmware and is generally referred to as the Logical Domains Manager. As with the Xen hypervisor, each virtual machine is securely executed on a single computer and runs its own guest Oracle Solaris operating system


paravirtualized machine (PVM)

A virtual machine with a kernel that is recompiled to be made aware of the virtual environment. Runs at near native speed, with memory, disk and network access optimized for maximum performance.

Paravirtualized guests use generic, idealized device drivers, which are part of the guest’s OS. The I/O operations using these generic device drivers are mapped to the real device drivers in dom0. The generic, abstracted drivers in the guest seldom change and provide excellent guest stability. The dom0 domain, alternatively, can use the native hardware vendor drivers, and the guests can safely migrate to another dom0 with slightly different drivers.

For other resources such as CPU and memory, paravirtualized kernels make special “hypercalls” to the Xen hypervisor. These hypercalls provide better performance by reducing the number of instructions and context switches required to handle an incoming request. By contrast, on an emulated (hardware virtualized) guest, driver requests engage the guest’s interrupt handler, increasing the I/O operation overhead.


refresh server

An Oracle VM Server dedicated to handling file system refreshes on behalf of a server pool. A refresh server temporarily mounts file systems on an NFS file server during the refresh operation. The server must be granted full data access in order to perform the refresh. For each NFS file server, at least one Oracle VM Server from each server pool accessing the file server must be assigned as a refresh server.


server pool

Server pools logically organize one or more Oracle VM Servers into groups where virtual machines can run.

Each server pool can have up to 32 physical servers. Each Oracle VM Server can be a member of only one server pool. The server pool is the operational unit of Oracle VM. Policies are configured and enforced at the server pool level.

A minimum cluster of three Oracle VM Server nodes in each server pool is strongly recommended for high availability. If one node in the cluster experiences a hardware failure or is shut down for maintenance, failover redundancy is preserved with the other two nodes. Having a third node in the cluster also provides reserve capacity for production load requirements.

server processor compatibility group

A server processor compatibility group is a group of Oracle VM Servers with compatible processors, or CPUs sharing the same processor family and model number. These groups are created to ensure that a virtual machine running on one Oracle VM Server can safely be migrated and continue to run on another Oracle VM Server. Oracle VM Manager automatically creates processor compatibility groups as it discovers servers that have different processor types.

Using Oracle VM Manager you can create custom compatibility groups to improve your ability to do smooth migrations and to group servers according to your own requirements.

sparse copy

A clone of the type "sparse copy" is a disk image file of a physical disk, taking up only the amount of space actually in use; not the full specified disk size.

See Also: non-sparse copy

Storage Connect

Oracle VM integrates with all types of storage, referred to as generic storage, but also provides advanced storage functionality for storage vendors that provide a plug-in to access their storage. This plug-in is part of Oracle VM’s Storage Connect framework.

Oracle VM provides its own Oracle VM Storage Connect plug-in for the Sun ZFS Storage Appliance, and for the Oracle Axiom systems.


thin clone

A thin clone is a clone of a virtual disk that takes up only the amount of disk space actually in use; not the full specified disk size.

Thin cloning of virtual disks on OCFS2-based repositories is supported. Thin provisioning of physical disks on generic storage is not supported.


virtual appliance

A package created as a single .ova (Open Virtualization Format Archive) file or a set of .ovf (Open Virtualization Format) and .img (disk image) files. Virtual appliances contain one or more virtual machines and include the virtual disks and the inter-connectivity between the virtual machines.

In previous releases, virtual appliances were known as assemblies.

virtual disk

A file or set of files, usually on the host file system although it may also be a remote file system, that appears as a physical disk drive to the guest operating system.

virtual machine (VM)

A guest operating system and the associated application software that runs within Oracle VM Server. May be paravirtualized or hardware virtualized machines. Multiple virtual machines can run on the same Oracle VM Server.

virtual machine template

A template of a virtual machine. Contains basic configuration information such as the number of CPUs, memory size, hard disk size, and network interface card (NIC). Create virtual machines based on a virtual machine template using Oracle VM Manager.


A layer-2 network may be segregated into partitions, at the switch or router, so that network traffic is isolated to a distinct broadcast domain. VLANs can be tagged so that a trunk can transport data for all of the different VLANs in a network.

VLANs are commonly used in large networks to help simplify network design, provide mechanisms to achieve better scalability, and to improve security.