Red Hat (RHT) seems to have cornered the market for open source distributed software-defined storage systems. This week, the company announced that it will acquire Inktank, the company behind Ceph—the major open source alternative to GlusterFS, which Red Hat already owns.

Developed beginning in 2004, Ceph became the basis for the creation of Inktank in 2012 by Sage Weil, one of the lead Ceph developers. Since then, Inktank has offered support services for Ceph, an increasingly important storage platform for OpenStack and other public and private cloud environments.

Red Hat is paying about $175 million to acquire Inktank, which will likely prove to be money well spent. Since Red Hat already controls GlusterFS, which it purchased in 2011 and currently uses as the basis for Red Hat Storage Server, the company now stands as indomitable leader of the open source software-defined storage ecosystem.

Of course, “open source” is one of the operative words there. Controlling both the Gluster project and Inktank does not mean Red Hat will monopolize software-defined storage, since the code behind both organizations remains entirely free and open source, and availble to Red Hat’s competitors.

Still, the acquisition puts Red Hat in a great position to expand its open source distributed storage offerings, and to continue integrating open source storage for the cloud with open source cloud infrastructure solutions such as OpenStack. And it signals a big shift since Inktank’s earlier days, when it seemed to be forging closer ties with Canonical, a Red Hat competitor, as Red Hat focused on Gluster.

Red Hat says it expects to complete the Inktank acquisition by the end of May 2014.