Five years after purchasing VMware, EMC is becoming more aggressive in selling its own products and services alongside those of its virtualization subsidiary.

In the six months since firing VMware CEO Diane Greene, who had battled to keep the subsidiary as independent as possible, EMC has strengthened integration between its storage and VMware's hypervisor; unveiled replication software for VMware environments; updated data-protection software to improve backup for VMware customers; and acquired 500,000 additional shares of VMware stock.

Most recently, EMC became certified as a gold-level VMware Authorized Consultant (VAC), allowing the storage company to offer strategy, design and implementation services to VMware customers.

Greene, who was ousted in July and replaced with former Microsoft executive Paul Maritz, had always lobbied for VMware's independence, telling Network World just weeks before her departure that VMware relies heavily on partners and must be able to "execute in an unfettered way."

EMC today is making defensive moves against other storage vendors, because server virtualization is a huge driver for the purchase of networked storage systems, says Forrester Research analyst Andrew Reichman.

"The needle is definitely swinging," Reichman says. "[EMC is] less scared to come out and say 'we're the best choice.' I don't think it's swaying all the way to the point where VMware is going to box out other partners or denigrate them. But I think they are pulling the gloves off, to some extent."

EMC executive Howard Elias acknowledges that the company has stepped up marketing efforts with regard to how its own products relate to VMware's.

"There's definitely more focus and emphasis on communicating more crisply and forcefully out to the marketplace that our products and services are well enabled and in tune with the VMware technology," says Elias, the president of EMC's Global Services & Resource Management Software Group. "It is fair to say in earlier times we were not as bold out in the marketplace about our leadership position and our infrastructure and services around virtualization."

While VMware has partnerships with EMC competitors such as IBM, NetApp, Fujitsu, Sun and Dell, EMC had not joined the VMware Authorized Consultant program until this month.

"I would argue we probably took that too far and created even somewhat of an unlevel playing field in that EMC was not able to work with mutual customers on integration solutions," Elias says.