Half of VMware's customer base is virtualising Microsoft Exchange and 65% virtualise SQL Server, but the majority of VMware customers are not virtualising SAP and Oracle applications, according to survey data released by VMware.

VMware, which makes the most widely used x86 server virtualisation software, revealed the data to illustrate that virtualisation is robust and secure enough for customers to place critical applications inside virtual machines. However, the results, based on a survey of 1,083 customers in the United States, Europe and Asia, also show there is still much room for growth when it comes to virtualising important business workloads.

While 65% of VMware customers who use Microsoft's SQL Server have virtualised at least one instance of the software, only 43% of total SQL workloads are inside VMs. A similar trend occurs with Microsoft Exchange: 50% of customers virtualise at least one instance of Exchange, but only 38% of total instances are virtualised.

The opposite is true with Microsoft SharePoint. While only 41% of customers have virtualised SharePoint, a total of 53% of SharePoint instances are in VMs. "I think the percentages are definitely higher than most people think," says Gaetan Castelein, a product marketing executive for mission-critical application virtualisation at VMware.

The data may not tell the whole story, however. Just because a customer virtualises Exchange does not mean the customer is virtualising all aspects of Exchange, says Gartner analyst Chris Wolf. A customer might put a front-end server that routs messages into a VM, but keep mailbox servers and databases in physical servers because they have higher I/O requirements, he says.

Beyond Microsoft applications, the VMware survey data also shows adoption of virtualization is significantly smaller when it comes to SAP and Oracle. Thirty-four percent of VMware customers virtualize Oracle database, 20% virtualize Oracle Middleware, and 12% virtualize SAP applications.

The total number of instances running inside virtual machines is 25% for both Oracle database and middleware, and 18% for SAP apps. VMware conducted the survey in January, and showed results to analysts at the recent VMworld conference, but has not published them. Because the survey occurred nine months ago, the percentage of customers virtualizing mission-critical applications could be higher today.

There are hundreds of types of applications in VMs, but VMware just asked customers about the six listed above to get a sense of adoption related to some of the most common mission-critical applications.

Although SAP and Oracle apps are far less likely to reside in VMs than Microsoft tools, VMware executives says that disparity is not related to technical problems. Customers typically pair virtualisation deployments with server refreshes and application upgrades. Microsoft software applications are updated far more frequently than SAP's and Oracle's, VMware executives say. SAP and Oracle apps have by and large not yet been virtualised because customers are reluctant to make big changes in between upgrade cycles.

"Rule Number 1 in IT is, if it's not broken don't fix it," says Bogomil Balkansky, VMware's vice president of product marketing.Wolf, however, chalks up the SAP/Oracle virtualisation numbers in part to the criticality of the workloads. "Prior to this year, we didn't have hardware that was capable of running those types of VMs well, at least in an enterprise scale," Wolf says.

Oracle's complicated licensing rules have also limited virtualisation adoption, he says. Within the entire VMware install base, 34% of workloads are virtualised. That percentage is higher than the entire IT population, of course, because a company wouldn't be a customer of VMware if it hasn't adopted virtualisation.

Network World's recent State of the Network Study, which polled 311 IT organisations, shows that most enterprises are virtualising at least some tier-1 applications. Twenty-two percent have a limited deployment in virtualising tier-1 apps, 18% are in the process of deploying enterprise-wide, and 12% have fully implemented a program to virtualise tier-1 apps. Another 29% are researching, testing or piloting such a program. Companies with at least 500 employees are reporting higher virtualisation rates than their smaller brethren.

Various surveys have found that more than half of newly deployed workloads are being placed in VMs. If that trend holds up, the total number of VMs could eventually pass the number of physical servers.

Another interesting tidbit revealed by VMware is that their average customer is attaining consolidation ratios of five to one, or five VMs per socket. An average two-socket server, then, holds 10 VMs.

But those consolidation ratios can vary quite a bit. With SQL Server, VMware has seen some customers achieve ratios of 20-to-1, Castelein says. For Exchange, five VMs per socket is more often typical. VMware says that's due less to technical limitations than it is to customers' comfort level, and not wanting "to put too many eggs in one basket."

Wolf agreed with VMware's assessment that virtualisation's performance issues have essentially been solved, particularly with the release of new virtualisation-enabled hardware from AMD and Intel. However, enterprises with strict requirements still have concerns about security, and may not accept the idea of putting multiple security zones onto the same physical server, he says.