NetApp executives played down the speculation. They said they didn’t need a backup platform, but they wanted Data Domain because its leading position in data deduplication for backup was disruptive and driving strong revenue growth. EMC, which paid $2.1 billion to outbid NetApp for Data Domain, has continued to grow that business despite a plethora of competitors.

NetApp has since made several smaller acquisitions – the largest was LSI’s Engenio systems division – but stayed away from backup. But a few rough quarters have caused NetApp’s stock price to shrink, and now the rumors have returned that it is hunting for backup.

A Bloomberg story today pegged backup software vendor CommVault and disk and tape backup vendor Quantum as the main targets. The story was based more on speculation from Wall Street analysts than sources who said any deals were in the works, but such an acquisition wouldn’t surprise many in the industry.

“I think NetApp needs to acquire companies and technologies, and bring in talent from the outside,” Kaushik Roy, managing director of Wall Street firm Merriman Capital, told Storage Soup.

CommVault and Quantum were among the companies believed to be on NetApp’s shopping list in 2009. A few things have changed. NetApp signed an OEM deal to sell CommVault’s SnapProtect array-based snapshot software earlier this year. That deal is in its early stages. NetApp hasn’t sold much CommVault software yet, but perhaps the partnership is a test run for how much demand there is and could lead to an acquisition.

Quantum was EMC’s dedupe partner before it bought Data Domain. If NetApp bought Quantum in 2009, it could’ve been taken as NetApp picking up EMC’s leftovers. But Quantum has revamped its entire DXi dedupe platform since then, expanded its StorNext archiving platform and acquired virtual server backup startup Pancetera. Those developments could prompt NetApp to take another look.

There are also smaller dedupe vendors out there, most notably Sepaton in the enterprise virtual tape library (VTL) space and ExaGrid in the midrange NAS target market.

However, people who suspect NetApp will make a move expect it will be a big one. CommVault would be the most expensive with a market cap of $1.9 billion and strong enough revenue growth to stand on its own without getting bought. Quantum, which finally showed signs of life in its disk backup business last quarter, has a $524 million market cap but most of its revenue still comes from the low-growth tape business.

Storage technology analyst Arun Taneja of the Taneja Group said buying CommVault would make the most sense if NetApp wants to take on its arch rival EMC in backup. While NetApp was the first vendor to sell deduplication for primary data, it is missing out on the lucrative backup dedupe market.

“NetApp needs to get something going in the data protection side,” Tanjea said. “They’ve missed millions of dollars in the last two years [since EMC bought Data Domain].

“If they want to be full competitors against EMC – and what choice do they have -– CommVault would be better for NetApp to buy. In one fell swoop, CommVault covers a lot of ground against EMC — backup software, dedupe technology at the target and source, and archiving, too.”

EMC president Pat Gelsinger said EMC had already moved on by the time Dell officially ended their storage partnership last week after a 10-year relationship.

Gelsinger said it was no secret that EMC’s partnership with Dell had to drastically change or end after Dell expanded its storage presence by acquiring EMC competitors EqualLogic and Compellent.

“It got to a natural point where the relationship had to be restructured or it had to come to an end. Unfortunately, it came to an end,” Gelsinger told a group of reporters last Thursday at EMC Forum 2011, held at Gillette Stadium in Foxborough, Mass.

Dell sold EMC’s Clariion, Celerra, Data Domain and VNX systems through OEM and reseller deals, with the bulk of the revenue generated from Clariion midrange SAN sales. Dell will also no longer manufacture EMC’s low-end Clariion.

Dell’s revenue sales for EMC’s channel have been sliding downward since last year, Gelsinger said. EMC reported Dell-generated revenue of $55 million in the fourth quarter of 2010, and that fell to under $40 million in the first quarter of this year. EMC has not given a figure for Dell revenue since then, but its executives said its non-Dell channel sales for the mid-tier increased 44% year-over-year in the third quarter of this year.

EMC has built up its channel this year, making the SMB VNXe product a channel-only offering that directly competes with Dell products. Earlier this month, EMC launched a channel-only Data Domain DD160 SMB system.

EMC has also continued to upgrade its VNX midrange platform. Last week it launched an all-flash model (VNX5500-F) as well as a high-bandwidth VNX5500 option with four extra 6 Gbps SAS ports, and support for 3 TB SAS drives throughout the VNX family.

“Now that we are no longer continuing forward [with Dell], we have to do it ourselves,” Gelsinger said. “It’s a clear, simple focus on our part.”

Dell began selling EMC storage in 2001, and in late 2008 the vendors said they were extending their OEM agreement through 2013. Dell also widened the deal in March 2010 by adding EMC Celerra NAS and Data Domain deduplication backup appliances to their OEM arrangement. However, the relationship had already started to deteriorate by then, going back to when Dell acquired  EqualLogic in early 2008.

The rift became irreparable last year when Dell followed an unsuccessful bid for 3PAR by completing an $820 million acquisition of Compellent in December.

Customers who purchased EMC storage from Dell will continue to receive support, Dell said in a statement, but it is ending its OEM and reseller deals for EMC Clariion, Celerra, Data Domain and VNX systems.

The move isn’t much of a surprise, considering Dell had already driven a large wedge into the relationship by buying its own storage companies – including several direct competitors to EMC.

Dell has sold EMC storage since 2001, and in late 2008 the vendors said they were extending their OEM agreement through 2013. Dell also widened the deal in March of 2010 by adding EMC Celerra NAS and Data Domain deduplication backup appliances to their OEM arrangement. However, the relationship had already started to deteriorate by then, going back to when Dell acquired EMC competitor EqualLogic in early 2008. The rift became irreparable last year when Dell followed an unsuccessful bid for 3PAR by completing an $820 million acquisition of Compellent in December.

Dell also acquired data reduction vendor Ocarina and the assets of scale-out NAS vendor Exanet in 2010, giving it more storage IP to integrate with its platforms.

Even before Dell bought Compellent, EMC CEO Joe Tucci a year ago said the once tight relationship between the vendors “cooled off” after Dell tried to buy 3PAR. A Dell spokesman responded by saying EMC still played an important role in Dell’s storage strategy.

There has been no OEM deal for EMC’s VNX unified storage system launched last January, although Dell did have an OEM deal for the Clariion and Celerra platforms that VNX replaced. EMC has built up its channel this year, making the SMB VNXe product a channel-only offering that directly competes with Dell products. Last week EMC launched a channel-only Data Domain DD160 SMB system.