CLOCKSS has a centralized organization but a distributed implementation. Efforts are under way to reconcile the completely centralized OAIS model with the reality of distributed digital preservation, as for example in collaborations such as the MetaArchive and between the Royal and University Library in Copenhagen and the library of the University of Aarhus. Although the organization of the CLOCKSS Archive is centralized, serious digital archives like CLOCKSS require a distributed implementation, if only to achieve geographic redundancy. The OAIS model fails to deal with distribution even at the implementation level, let alone at the organizational level.It is appropriate on the 19th anniversary of the LOCKSS Program to point to a 38-minute video about this issue, posted last month. In it Eld Zierau lays out the Outer OAIS - Inner OAIS model that she and Nancy McGovern have developed to resolve the mis-match, and published at iPRES 2014.
They apply OAIS hierarchically, first to the distributed preservation network as a whole (outer), and then to each node in the network (inner). This can be useful in delineating the functions of nodes as opposed to the network as a whole, and in identifying the single points of failure created by centralized functions of the network as a whole.
While I'm promoting videos, I should also point to Arquivo.pt's excellent video for a general audience about the importance of Web archiving, with subtitles in English.