The next step in Dominos virtualization adoption was allowing VMwares technology to work with the companys SANalso a relatively new enterprise-class technology in late 2004 and early 2005. This was an important step for Dominos because it would mean linking its first virtualized servers together. The problem at the time, McCracken said, was that VMware had not certified the SAN that Dominos built. All the benefits that come with VMwares technologysuch as high availability; VMotion, which allows all working processes to continue throughout a migration to a new host; and backup featuresrequire SAN access.While the IT department was able to connect the few VMware systems to the SAN, the main roadblock, said Jeff Lang, another of Dominos senior network engineers, was that without certification from VMware, there was no one to call for support if something went amiss. However, that did not stop Lang and McCracken from trying to do as much as they could with what was available. At one point, the IT department was running Windows Compute Cluster Server software with help from a Microsoft patch.Pund-ITs King said the problems with VMware and SANs were common issues that have now been addressed to an extent. "There were some issues with initial x86 virtualization solutions and SANs, particularly as to the SAN being able to recognize individual virtual servers hosted within physical servers," King said. "That issue has been resolved via highly granular management applications, which can also be used to measure usage [and] performance of specific applications and processes within virtual servers, thus providing the means to create accurate SLAs [service-level agreements] and chargeback mechanisms." By mid-2005, Dominos executives had seen enough tests and had grown comfortable enough with the technology that the IT department had a freer hand in preinstalling VMware software when new servers were delivered. That initial deployment of replacing the one aging Compaq server grew to four systems that were plugged into the companys nascent SAN and, eventually, to the current 17 systems with preinstalled virtualization software. "Unless you have a really good reason, were not going to buy a physical machine just for the box unless its a large database or something that requires a lot of horsepower," McCracken said. "Were just going to virtualize it." By early 2007, Dominos had 11 servers in its main data center running virtualization technology and six others in remote data centers that used VMwares ESX Server software. All told, these 17 machines contain approximately 80 virtual environments, a number that could double or triple when the company installs a new SAN, developed by EMC and certified by VMware. Now the IT department has started to expand the reach of virtualization beyond the main data center in Ann Arbor and is seeking to maximize the technologys use in remote sites used for backup and disaster recovery. Dominos is using ESX Server to remotely control and monitor the virtual environments at two locations. Starting late last year, Dominos invested in the latest version of ESX Server3.0and began moving its internal e-mail application onto systems with virtual environments. McCracken has started to use virtualization for making adjustments to applications. Instead of hoping that the changes will take, he said he uses VMwares built-in rollback function to test changes before they are deployed on the network. "Its like you took a ghost image of the machine, and you know its exactly like it was before, and ... you know its going to work," McCracken said. "Its really hard to express how nice of an advantage that is because the last thing that I did it for was a RADIUS server. When you have thousands of stores connected [to the system], and if you cant get it set up, then you cant get your data, and the whole management team is going to be looking at you when they cant get that data because you were the one that upgraded this machine." The companys developers have also begun using the technology to develop and test applications in a virtual environment and then return the virtual image to the IT department, where its checked for security and other flaws before its deployed on the network. Check out eWEEK.coms for the latest news, views and analysis on servers, switches and networking protocols for the enterprise and small businesses.