Emc defended itself against storage vendors including NetApp by agreeing yesterday to acquire peer Isilon Systems for $2.25 billion.

NYPost.com broke the news of the deal Sunday evening.

EMC’s shares fell 1.2 percent yesterday to $21.45, while Isilon’s rocketed to $33.77, a 28-percent gain.

FBR Capital Markets, in a report, considered the price paid — seven times projected 2012 revenue — a “fair valuation.”