"In response to EMC's revised, unsolicited offer, the NetApp Board of Directors will carefully weigh its options, keeping in mind both its fiduciary duty to its stockholders and its disciplined acquisition strategy," NetApp CEO Dan Warmenhoven said in a statement. He promised an update "shortly."

EMC Corp. to purchase Data Domain from $1.8 billion to $2.1 billion, once again one trumping NetApp, which had offered $1.9 billion.

EMC said that offer stands until midnight July 17.

While Data Domain has scheduled a special stockholders meeting on Aug. 14 to consider and vote on the NetApp merger proposal, EMC's offer is different from a merger agreement and Data Domain's stockholders need only decide to sell their shares to EMC by July 17.

Meanwhile, in an interview with Computerworld, an EMC executive argued that his company's offer is the most logical one for Data Domain shareholders. Matthew Olton, worldwide head of mergers and acquisitions at EMC, said his company is "dramatically" larger than NetApp and far more capable of infusing money into Data Domain to increase product development and worldwide marketing and sales. NetApp last year had $3.4 billion in sales while EMC reported $14.8 billion.