In a letter to customers notifying them of the situation, Coraid CEO Kevin Brown said he hopes to continue selling the ZFS-based NAS appliance after a long-standing legal dispute between NetApp and Sun (now Oracle) gets settled.

“We hope to reinstate our Z-Series offering in the coming months,” Brown wrote to customers, after noting that the ZFS file system has been downloaded nearly one million times by customers and vendors.

“We made the decision to suspend shipment after receiving a legal threat letter from NetApp Inc., suggesting that the open source ZFS file system planned for inclusion with our EtherDrive Z-Series infringes NetApp patents.”

NetApp filed a lawsuit against ZFS creator Sun in 2007 claiming patent infringement and Sun promptly countersued. The suits were still pending when Oracle acquired Sun, and now Oracle and NetApp are attempting to settle out of court.

Coraid launched its Z-Series May 19, adding the NAS device to its ATE over Etherenet (AoE) SAN platform. Brown said Coraid is still selling the SAN systems, which are not affected by the NetApp patent charge.

In his letter to customers, Brown included a letter dated May 26 that he received from Edward Reines, a patent litigation attorney from Weil, Gotshal and Manges LLP who represents NetApp in its ZFS litigation. Reines’ letter read in part: “Coraid must cease infringement of NetApp’s patents and we reserve our rights to seek all appropriate remedies for any infringement.”

The letter to Brown points out that Coraid uses the term “unified storage” to describe the Z-Series, and NetApp’s patents involved in the litigation with Sun “cover a host of features, including unified storage …”

Brown, who served as VP for NetApp’s Decru security platform for 18 months before joining Coraid, apparently took the NetApp threat seriously.

His letter to customers didn’t say how many if any have purchased the Z-Series, only that Coraid has received “dozens of customer inquiries.”

Compellent, which is more competitive with NetApp than Coraid is, launched its zNAS system based on ZFS in April. If Compellent has been threatend by NetApp, it hasn’t said so publicly.