Network Appliance has sued Sun and its prized Zettabyte File System (ZFS), which Sun open sourced, charging seven counts of patent infringement.

ZFS is one of the few innovations in Solaris that the open source community appears to be interested in and a point of some pride to Sun.

In a statement Sun called the suit "a direct attack on the open source community."

Sun CEO Jonathan Schwartz, apprised of the suit by a large Sun shareholder, blogged about the "the futility of litigation as a mechanism for proprietary companies to stifle the rise of open source competition."

The suit comes in retaliation for Sun privately claiming that NetApp infringes three disk virtualization patents that it acquired when it bought StorageTek, allegations that StorageTek was making to NetApp at the time of its acquisition three years ago. Or so the suit says.

NetApp wants the Texas district court where it filed suit (yup, Lufkin, Texas) to find the three patents it says Sun keeps waving under its nose asking for royalties invalid on the basis of prior art and it wants treble damages for Sun's alleged willful infringement of seven NetApp patents. It also wants an injunction halting further distribution of ZFS.

NetApp contends that it doesn't even use the technology covered in the three Sun patents, but Sun won't listen. Sun's systems and software, primarily ZFS, however, are supposed to tread on NetApp's IP.

The 18-page suit says Sun is "aggravating the situation" by distributing "ZFS technology to others to induce others to adopt and distribute the infringing technology in their products without informing them of NetApp's applicable patents."

The US patents NetApp claims Sun infringes are entitled:

· "Method for maintaining consistent states of a file system and for creating user-accessible read-only copies of a file system" (No. 5,819,292);
· "Copy on write file system consistence and block usage" (No. 6,892,211);
· "Multiple concurrent active file systems" (No. 6,857,001);
· "File system image transfer" (No. 7,174,352);
· "Method for writing contiguous stripes in a RAID storage system using mapped block writes" (No. 7,200,715);
· "System and method for representing named data streams within an on-disk structure of a file system" (No. 7,162,486);
· "RAID assimilation method and apparatus" (No. 7,133,964).

The three Sun patents NetApp claims aren't valid include US Patent Number 5,403,639 ('639) - "File server having snapshot application data groups" - which NetApp claims is a dead ringer for US Patent No. 5,410,667 ('667), which Sun also owns, and that the '639 inventors and its filers "withheld" the similarity between '639 and '667 from the US Patent Office "with the intent to deceive" the agency.

Sun supposedly alleges that NetApp infringes both '639 and '667. NetApp says there's loads of prior art on '667, which is about a "Data record copy system for a disk drive array data storage subsystem."

NetApp also wants Sun's US Patent No. 6,581,185, entitled "Apparatus and method for reconstructing data using cross-parity stripes on storage media," thrown out.

In his blog, Schwartz claims "Sun did not approach NetApps about licensing any of Sun's patents" and says "NetApps first approached StorageTek behind the cover of a third-party intermediary seeking to purchase STK patents," which Sun wouldn't do when it acquired StorageTek but "instead of engaging in licensing discussions, NetApp decided to file suit to invalidate them."