PolyServe, the clustering outfit, has picked up $20 million in D Series funding from Fidelity Ventures, Greylock, New Enterprise Associates and the RODA Group intending to use the money, which it called an “operating cushion,” to accelerate sales.

It said the money would last it “well beyond” profitability. It has already burned through $43.5 million.

Having cut its teeth on Linux, PolyServe expanded into Windows this spring with the launch of Matrix Server, shared data cluster software for Windows, as well as integrating server software with NAS storage.

It claims 300 customers worldwide including Wells Fargo, Burlington Coat Factory and Amerada Hess and is now a buddy of Microsoft’s and HP’s.

Meanwhile, PolyServe has cut an OEM agreement with Fiserv Imagesoft, which is going to bundle PolyServe’s storage clustering software, both in its Linux and Windows flavors, with its financial management software. The combine will start with Fiserv’s Guardian Series platform, which validates checks. Fiserv will use the stuff to create clusters of up to 16 industry-standard servers attached to a SAN.