The two categories of software that are becoming critical requirements for large-capacity data centers in virtualized environments are performance monitoring and capacity management. Quest Software makes a performance monitoring tools suite called Foglight, which includes a capacity management tool called vFoglight. In a company blog post last August, Quest product manager Derrek Seif admitted that companies need both categories, and made the case for customers to use Foglight performance monitoring as a tool for capacity management.

"Now, we are leveraging our performance monitoring expertise as a key component for solving capacity management challenges," Seif wrote. "The 'interrelationships' achieved between performance monitoring and capacity management are critical in preventing poor application and infrastructure performance, reducing wasted virtual infrastructure resources, and accurately forecasting growth to support the business." But sometimes leverage alone isn't enough to achieve interrelationships; what companies may require instead are deals.

This morning, Quest announced a deal to acquire VKernel, the maker of a capacity management tool called vOPS, in a deal VKernel's chief marketing officer described this morning as causing no collateral attrition for his company whatsoever.

"The same team that has built, sold, and supported your products is still here. In fact, we are continuing to expand and hire in development, QA, sales, and support," wrote VKernel's Bryan Semple. Adding that the next edition of VKernel tools will be released in just a few weeks' time, Semple went on to say, "The main difference for our customers is that we now have the financial backing and support of a publicly traded company."

Virtualization leader VMware positions itself in the market as the provider of every VM management tool an enterprise could possibly use. To that end, it has established vSphere as an obvious metaphor for all-encompassing tools, which makes it necessary for anyone competing in VMware's sphere, as it were, to be able to deploy a similar metaphor.

Quest seemed to be doing quite well with vFoglight just as a management tool, with journalist Bernd Harzog reporting last August that more vSphere customers had installed vFoglight's capacity management tool than vSphere's own, or any other company's, for that matter. But VKernel was getting some positive reviews, and making inroads as a more preferable tool for performing more sophisticated predictive analysis, applying current usage trends to reveal graphs of potential capacity usage over time.

That, and VKernel was striking all the right chords in its battle for customer mindshare against VMware. Last July, VMware introduced a controversial new licensing model that charged customers based on the total amount of pooled virtual RAM apportioned by the VMs they create, as opposed to the physical resources those VMs use. It was supposed to be a revolutionary model, but customer opposition grew so rapidly (imagine "Occupy vSphere!") that VMware had to rethink its pricing limits last August. Still, perhaps as a parting shot in the direction of protesting customers last October, VMware CEO Paul Maritz warned that future implementation of "vRAM licensing" could move back in the direction VMware originally intended.

VKernel was one of the companies leading the charge against the vRAM model, advocating instead a more utility-like model derived from how cloud providers charge their customers. In a company blog post last month, VKernel's Semple wrote, "VMware's main argument for consumption-based pricing is around the economics of the cloud. Yes, customers of clouds will most likely be billed based on consumption. But an overwhelming majority of the infrastructure powering the cloud will be fixed priced. With the exception of power, nearly all cloud infrastructure assets are based on purchasing fixed units of a physical resource... Consumption-based pricing is simply an added burden for virtualization administrators without any appreciable benefit for the customer."

Quest had also been experimenting with newer licensing models, including a perpetual capacity-based option for its NetVault backup service. So VKernel's public skewering of VMware may have hit all the right notes. If vOPS is the surviving product in the deal, the fate of vFoglight may need to be determined. Does vOPS become the new vFoglight, or will the two products co-exist somehow?