NetApp, which filed its lawsuit Wednesday in a U.S. District Court in Texas, alleges Sun violates patents relating to data processing systems and related software.
NetApp is asking the court to issue a permanent injunction against Sun to prevent it from further developing ZFS and offering it commercially or creating derivatives of the software.
ZFS, which endows servers with vast storage capacity, high data integrity and easier networked storage administration, is one of the key features introduced in Solaris 10. Sun executives frequently cite ZFS as evidence of the company's engineering skill, and it's one of the few Solaris features that has caught the attention of Linux programmers who often consider Solaris a relic from an earlier age.
In addition to the patent violation claims, NetApp is asking the court to declare that it has not violated three of Sun's U.S. patents and to find them invalid.
Sun disputes the basic claims that ZFS violates NetApp's patents and that the Sun patents are invalid. The company tried to position the lawsuit as an attack on open-source programmers and users.
"NetApp's legal attack against Sun's open-source ZFS solution which is freely available in the marketplace is a clear indication that NetApp considers Sun technology a threat and is a direct attack on the open-source community," Sun said in a statement. "Sun indemnifies its customers and stands behind the innovations we deliver to the marketplace."
Sun approached NetApp about 18 months ago with claims the storage maker was violating its patents and seeking a licensing agreement, NetApp Chief Executive Dan Warmenhoven said in a statement.
Several months into those discussions and following a review of the matter, NetApp made a discovery of its own, Warmenhoven said, concluding NetApp did not infringe the patents but that Sun infringed on NetApp's.
In April, talks between the companies broke off.
"Sun shifted from an aggressive position to not returning calls," Warmenhoven said.
Compounding the disagreement between the parties, Sun released ZFS as open source to users under its.
NetApp has no plans to pursue litigation against those who are using ZFS open source for educational purposes, research or other means that do not compete with NetApp, said Dave Hitz, NetApp founder and executive vice president.
And despite its lawsuit against Sun, NetApp has no intention of asserting its claims against its customers or Sun's customers, Hitz noted.
NetApp executives said they doubt a resolution will be reached with Sun before the courts rule on the case. They estimate a decision could be reached as soon as 12 to 18 months.
"Our objective is to get this resolved as soon as possible," Warmenhoven said.
CNET News.com's Stephen Shankland contributed to this report.