Friday May 08, 2009

Oracle VM Blog: Basics of Oracle VM

I'd like to cover some basics about Oracle VM, what's the difference between Oracle VM and RHEL Xen and how it's related to the open source Xen hypervisor.

Oracle VM ( is Oracle's server virtualization and management solution for x86/x86-64 platforms. The components of Oracle VM are Oracle VM Manager and Oracle VM Server.

* Oracle VM Manager: Provides the web based user interface to manage Server Pools, Oracle VM Servers, virtual machines, and resources. Oracle VM Manager not only provides life cycle management of virtual machines such as creating and configuring guest VMs, but also performs advanced functionality to load balance across resource pools and automatically reduce or eliminate outages associated with server downtime.

* Oracle VM Server: A self-contained virtualization environment designed to provide a lightweight, secure, server-based platform for running virtual machines. Oracle VM Server is based on open source technology (Xen hypervisor for example) tailored by Oracle, and includes Oracle VM Agent to communicate with Oracle VM Manager for management of virtual machines. Oracle VM Server is installed on bare metal server hardware.


Although Oracle VM server uses the Xen hypervisor, it's not the same as the one used in RHEL Xen. Similarly, both RHEL and SLES use the Linux kernel, but you won't say that one is repackaged from the other. Our development team compared the Xen source code between RHEL 5.2 Xen (3.1.0+ patches) and Oracle VM Server 2.1.2 (Xen 3.1.4), the diff file is 1.6MB, or 48,880 lines of code. It's not just a set of bug fixes or patches, there are big differences in what's actually deployed.

From a deployment perspective, multiple Oracle VM Servers are grouped into Server Pools in which every server in a given pool has access to shared storage, which can be NFS, SAN (Fibre Channel) or iSCSI storage. This allows VMs associated with the pool to start and run on any physical server within the pool that is available and has the most resources free. Given the uniform access to shared storage, VMs may also be securely Live Migrated or automatically (re-)started across any servers in the pool. The underlying core technology to form a server pool is the OCFS2 that Oracle developed and contributed to the Linux community, and accepted into Linux kernel 2.6.16. Obviously it's different in how the server pool is implemented in RHEL Xen or other Xen based solutions.


Oracle is a member of the Xen Advisory Board which serves in an advisory capacity to the Xen project leader for all community and development activities as well as management for the Xen trademark. Oracle's Linux and Oracle VM engineering team contributes heavily to feature development of Xen mainline software. The most significant contributions are in the area of hardware virtualized timers, guest and hypervisor debugger and bugfixes, transcendent memory, SSL live migration and xend locking, as well as participation in XenAPI changes; Oracle is also working on Windows Paravirtualized drivers. The Oracle QA team also provides stabilization efforts through testing Xen configurations with Oracle workloads and Oracle Enterprise Linux kernels.

See additional resources:

* Oracle's technical contributions to Linux and open source communities
* May 2009, OTN TechCast Linux Engineering Update with Wim Coekaerts: Part 2 - Virtualizing the Oracle Stack (8 minutes)
* May 2009, OTN TechCast Linux Engineering Update with Wim Coekaerts, Part 1 - Linux Kernel Development at Oracle (8 minutes)

Thursday May 07, 2009

Oracle VM: A Peek Into the Future

I haven't been blogging the last couple of weeks as I've had some internal deadlines, but luckily you've seen some good content from others on the Oracle VM team, including Honglin's entries below.

This time, I want to call your attention to a couple more blog entries from the team that are on another blog - this time the blog of my boss Wim Coekaerts, VP of Linux and Virtualization Engineering where he talks about some Oracle VM (or closely related...) projects that are particularly cool, namely our up-coming management CLI and webservices API, but also the OCFS2 "Reflink" project. Reflink is generically extremely useful for about any application, but is also intended to benefit Oracle VM in particular in expected up-coming releases.

These projects are expected to really increase the ability of users, integrators and other 3rd parties to automate processes around Oracle VM (API/CLI) as well as do things like radically improve performance and efficiency for things like cloning, provisioning, and snapshotting (Reflink).

Take a look.

Tuesday Apr 21, 2009

Oracle VM High Availability - Hands-on Guide to Implementing Guest VM HA

We just released a new White Paper: Oracle VM High Availability – Hands-on Guide to Implementing Guest VM HA. Guest VM HA functionality provides a powerful, easy-to-manage solution for maximizing up-time for virtually any guest VM workload, without requiring any tailoring inside the VM, making it simple to set-up, use, and maintain.

This white paper focuses on best practices of the Oracle VM Guest VM High Availability (HA) design and implementation. It's complementary to the previous White Paper: Oracle VM – Creating & Maintaining a Highly Available Environments for Guest VMs, and serves as a practical guide to help customers design the HA environment and experience the benefits of Oracle VM. It provides a step-by-step guide to plan and set up the Oracle VM environment so you can implement the guest VM HA feature to assure predictable, reliable, and accurate restarting of failed VM and Servers.

To implement HA, you must create a cluster of Virtual Machine Servers in a server pool and have them managed by Oracle VM Manager or Oracle Enterprise Manager Grid Control. Some basic steps include:

1. Installing Oracle VM Server and Manager
2. Creating Shared Storage for the Server Pool
3. Enabling HA for the Server Pool
4. Adding a new Server to the Server Pool
5. Enabling HA for the Virtual Machines

The most important part is to create shared storage for the server pool. You can set up shared storage for the server pool in the following configurations:

* OCFS2 (Oracle Cluster File System) using the iSCSI (Internet SCSI) network protocol
* OCFS2 using SAN (Storage Area Network)
* NFS (Network File System)

The procedures for creating shared storage for HA are essentially the same as what's described in the Oracle VM Server User Guide for creating a shared virtual disk using the above storage configurations for live migration. But you have fewer steps to go through when creating shared storage for HA. For example, you don't need to manually modify /etc/fstab for enabling HA since the configuration files will be handled by Oracle VM server agent automatically when you run /usr/lib/ovs/ovs-makerepo utility. In addition, the startup of related cluster services (o2cb) will also be handled when you run /usr/lib/ovs/ovs-cluster-configure utility.

One of the common mistakes is that when the network is not configured properly, the cluster configuration files such as /etc/ocfs2/cluster.conf won't be propagated correctly to each server of the server pool. For example, the loopback address ( may show up in the /etc/ocfs2/cluster.conf for some servers. You should verify your network settings (DNS, routing table, etc.), replace the loopback address with the public IP address for each server and make sure that the ocsf2 cluster configuration file (/etc/ocfs2/cluster.conf) be the same across all the servers within the same pool.

In summary, Oracle VM Guest VM HA functionality provides the following benefits:

* Auto-restart unexpectedly failed individual VMs on other servers in the server pool;
* Auto-restart all the guest VMs on another server in the server pool when an unexpected physical server failure occurs;
* Powerful cluster-based network- and storage heartbeat algorithms quickly and deterministically identify failed and/or isolated servers in the server pool to ensure rapid, accurate recovery;
* Sophisticated distributed lock management functionality for SAN, NFS, NAS, and iSCSI storage ensures VMs or entire servers can be rapidly restarted with no risk of data corruption.

For more information about Oracle VM and how customers are deploying it, please visit


Get the latest scoop on products, strategy, events, news, and more, from Oracle's virtualization experts




« April 2014