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Oracle VM – 4x More Marketing, 4x Fewer Substantiated Facts

by Avinash Nayak

The good folks in Oracle’s marketing department deserve a raise for their efforts around promoting the latest release of the company’s virtualization solution, Oracle VM (OVM) 3. They certainly are aiming high, claiming OVM 3 is four times more scalable than VMware, four times cheaper to deploy than VMware, and is architected for efficiency while VMware is prone to inefficiencies. Not bad for a product that did not even exist until 2009 and is only on its second release (why the second release is called OVM 3, I don’t know). Unfortunately for Oracle Marketing, there’s a problem, namely – the FACTS. The facts show that VMware vSphere 5 delivers much higher scalability, greater value and unmatched performance compared to OVM.

Let’s take a closer look at Oracle’s claims and compare them with the facts:

Is OVM 3 four times more scalable than VMware? Switch the order of the products and it's perfect.

Oracle bases this claim on the fact that OVM 3 supports 128 virtual CPUs (vCPUs) per VM, where vSphere 5 VMs support 32 vCPUs.

Wait. Did someone change the definition of scalability when we weren’t looking? Since when is the scalability of a virtualization platform defined only by the number of VM vCPUs supported?

Surely, a better measure of the scalability of a platform is the number of VMs doing useful work that the platform can support (and manage) on a host or a cluster. It’s not the only measure, but one that’s far more insightful for showing scalability than just comparing vCPUs. Oracle’s documentation shows that OVM 3 is only able to run up to 128 VMs per host, compared to 512 for vSphere 5 (four times more than OVM 3, what a coincidence). So, it looks like Oracle got the “four times” part right. They just got the products mixed up. Simple mistake.

In addition, VMware’s testing has shown that a 32 vCPU guests can deliver 92-97% of native performance. Oracle has yet to provide any evidence that a 128 vCPU guest can scale linearly on OVM3.0.

Is VMware four times more expensive than OVM 3? NO. Maybe Oracle meant vSphere has four times more functionality than OVM 3.

Oracle makes this claim solely based on virtualization software costs. But virtualization software cost is only one component of the total cost of deploying an application. The other components are the hardware costs (server, storage and networking), guest OS licensing costs, power and datacenter space costs. You need to take into account all of these when calculating the total costs for deploying an application.

Thanks to the advanced features provided by vSphere, customers are able to realize significant savings from reduction in hardware necessary to deploy an application environment relative to OVM.  Through the use of multiple advanced memory management features  (transparent page sharing, ballooning, memory compression, and hypervisor swapping), vSphere is able to achieve much greater VM density per host than OVM, meaning you need fewer hosts to deploy the same number of VMs. Independent tests have shown that vSphere 5 consistently delivers higher VM density compared to competing platforms, such as Xen based OVM.

Let’s take a simple example and compare the TOTAL cost of deploying 100 Linux VMs on vSphere 5 Enterprise Plus (VMware’s highest vSphere edition) vs. OVM3. We assume a conservative 25% density advantage for vSphere over OVM. This means that if we assume we deploy 12 VMs per host for OVM, we can deploy 15 VMs per host for vSphere 5.


We see that even the highest edition of vSphere 5 is less than 6% more expensive than OVM when you take into account TOTAL cost. So it appears that Oracle’s cost claims are exaggerated by 400/6 = 66.67 times.

So what do you get for a premium of less than 6%? Here’s a subset of the features found in vSphere 5 that are absent from OVM:



VMware vSphere 5 

Oracle VM 3

Clustered File System

VMFS 5 Purpose built and tested for virtualization

OVM built on OCFS2, not built for virtualization

Thin, bare-metal hypervisor

Yes, ESXi has a small 144MB footprint for better reliability and security

No, OVM 3’s Xen hypervisor requires a large Linux management partition making it four times larger

Logical resource pools

Yes, divide and assign cluster resources to hierarchical groups

No, users share all resources across entire server pool

Role-based access controls

Extensive customizable user roles and permissions

No, single user account used for all hosts managed by OVM Mgr

Storage live migration

Storage vMotion


Storage array support

Supports over 1,200 arrays, vSphere Storage APIs for Array Integration supported by 175 arrays

Storage Connect API supported by less than 20 arrays

Auto storage tiering

Profile-Driven Storage


Thin disks

Fully supported


Broad guest OS support

Over 88 guests

Only 13 guests

Complete resource balancing

DRS and Storage DRS, balances memory, CPU, storage load

DRS feature considers only CPU and network load

“Noisy neighbor” protection

Yes, Network and Storage I/O Controls


 HA policy enforcement 

 HA supports: admission controls, VM-VM affinity/anti-affinity controls, restart priority 

 HA feature supports only basic restart ; Only anti-affinity controls

Memory overcommit

Yes, enables greater VM density, lower costs


But Oracle should be intimately familiar with how a “free” solution does not necessarily provide better value. After all, isn’t MYSQL a free product (like OVM) and you only pay for support. Does it deliver the same capabilities as Oracle’s Enterprise Database solutions? I wonder what Oracle has to say about that.

Is OVM 3 more efficient than vSphere? We’d like to see the evidence.

The basis for this claim is a four year old Oracle VM Benchmark Performance Report from The Tolly Group done using OVM 2 (the first version of the product). The performance tests compare OVM 2 (note – Not OVM 3) to physical servers, not to vSphere. Oracle has not provided any evidence to support the claim that OVM 3 is more efficient or has a performance advantage over vSphere.

Like other Xen-based hypervisors, Oracle VM requires guest operating systems with extensive Xen paravirtualization modifications to get acceptable performance. Instead, vSphere uses unmodified guest OSs together with optimized device drivers and full support for virtualization hardware assist features in modern processors to deliver unmatched performance. This approach allows customers to use standard operating systems that are fully supported by ISVs. And with a disk footprint of only 144MB, the vSphere hypervisor represents a far smaller attack surface. An OVM 3 server’s disk footprint is swollen to 588MB (four times larger than vSphere) by the Linux management operating system installed in the Dom0 partition.

Also, without advanced features like Network and Storage I/O Controls, OVM is unable to guarantee service levels for business critical applications (for example, large databases.) vSphere is the only platform that delivers capabilities to ensure that your most important applications have access to the resources they need to meet required SLAs.

Grading the claims made by Oracle with regards to OVM 3:

Marketing: PASS; Delivering on the Marketing Claims: FAIL

So it looks like VMware will not be shutting shop just yet. Despite what Oracle says, vSphere 5 is well ahead of OVM 3 in terms of performance, features and value.

This blog is part of a series on Virtualizing Your Business Critical Applications with VMware. To learn more, including how VMware customers have successfully virtualized SAP, Oracle, Exchange, SQL and more, visit vmware.com/go/virtualizeyourapps.

13 thoughts on “Oracle VM – 4x More Marketing, 4x Fewer Substantiated Facts

  1. Lai L F

    Do you have a more detail breakdown of the cost comparison? Especially for the RHEL license cost? How do you arrive at different license cost when the number of RHEL VM deployed is the same? How do you achieve this kind of cost saving with VMware?

  2. Avi

    Hello Lai,
    As I mentioned in the notes below the cost comparison diagram, the RHEL licensing model used in the cost comparison is RHEL with unlimited virtual guests per pair of sockets ($3,249 with one year subscription). With this licensing model you are able to run unlimited RHEL VMs per pair of sockets. The cost comparison also assumes a 2 socket server. Therefore we are able to run unlimited number of RHEL VMs per server
    In the comparison, we assume we can run 12 VMs per server using OVM 3. With VMware’s 25% VM density advantage, we can run 15 VMs per server using vSphere 5.
    Based on the above parameters, to run 100 VMs, we would require 100/12 = 9 physical servers. We would therefore require 9 RHEL licenses. The total guest OS licensing cost would be 9*$3,249 = $29,241.
    For VMware, we would require 100/15 = 7 physical servers, requiring 7 RHEL licenses. The total guest OS licensing cost would be 9*$3,249 = $22,743.
    Similarly, VMware’s VM density advantage means we would require fewer hardware components (server, storage and networking) to build a virtual environment compared to Oracle VM.
    Hope this answers your question.

  3. Dominic Jones

    This article does not mention how Oracle software is only supported by Oracle in OVM when you virtualise. There are massive cost implications when you have to remove your Oracle environment from Vmware or any non Oracle VM before you can get you support call answered. Also when scaling business critical apps on demand in VMware, there is a massive manual intervention required with Vmware, again lots of hidden cost.

  4. Sanjo Thomas

    The cost comparison part is simply ridiculous. I have worked extensively on VMware and Oracle VM, in a very large environment. Let us take a simple server, a Dell r710 with 64 GB RAM. I need to run Linux VMs of 4 GB RAM I can only run 16 in Oracle VM and VMware. Both VMware and Oracle VM support thin disks as well. So I don’t understand the logic of VM density. Oracle VM runs Linux faster than VMware with paravirtualized kernels. I had tested it in our farms. The point of VMware being feature rich is well taken. Oracle’s VM Manager console is in stone age while VMware vCenter is light years ahead

  5. Sanjo Thomas

    WOW! Another, OCFS is not built for virtualization. OCFS 1.6 is built for virtualization and is used in OVM3. I was an initial used of this version of OCFS, and I had used the cloning technology of OCFS 1.6 to deploy large number of VMs in short time. Please be well informed before making such comments.

  6. Avi

    The blog post references the independent tests that show that VMware has a clear density advantage over other hypervisors, including Xen based hypervisors such as OVM. VMware’s density advantage is a result of the numerous memory management features in vSphere – transparent page sharing, ballooning, memory compression, and hypervisor swapping.
    Again, here is a link to the test:
    Oracle’s licensing, in general, does not allow 3rd parties to publish competitive benchmark results using Oracle’s products (unless approved by Oracle). But the tests clearly show that XenServer (another Xen based hypervisor) did not perform as well as vSphere.
    I am curious about the tests you performed. Would you be willing to share in more detail the methodology and results of your own tests with us?

  7. Sanjo Thomas

    Avi, glad to hear from you.
    OCFS2 is a general purpose cluster file system which provides high performance and high availability. Here I am talking about OCFS2 1.8\1.6, not earlier versions. The latest version of OCFS, OCFS2 1.8 is incorporated into Oracle VM Server 3 as virtual machine file system.
    All features needs for virtual machines such as thin-provisioning, cloning, snapshot, HA, distributed lock management, sharing the datastore across all nodes in the cluster, auto grow of file system (LVM), performance, and more is part of OCFS2 1.8.
    NetApp flex clone coupled with VMware VMFS and some script or tool allows us to clone large number of VMs real quick. It is a very nice feature.
    Exactly same thing is possible on OCFS2 (only from 1.6, 1.8 onwards), using native OCFS2 which have inbuilt deduplication mechanism. The difference here is, you can do the cloning on local disk, SAN, iSCSI. Anything that has an OCFS2 1.8 files system

  8. Charles

    This is absurd. On Oracle hardware, (servers only, storage can be anything) OVM licences cost NOTHING once you pay for support. Let’s say Larry charges a 20% premium for servers, which is about the state of things, looking at the chart above you are up for 12% of $133k which you had to spend anyway, because everyone takes out support, right? And if you use UEK instead of Redhat, that’s also FREE _AND_ redhat compatible, so I fail to see where the RH licences come into the picture at all. Unless you rely on features which are vmware-only–and there are plenty of sites where this is the case–you’d have to at least look at OVM.

  9. Stelios

    OVM is free (on Oracle HW) though. It may not be as feature rich as VMware but you cannot beat the value OVM offers. VMware license costs are absolutely ridiculous.


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