The case for active block layer extensions

Self-managing storage systems have recently received attention from the research community due to their promised ability of continuously adapting to best reflect high-level system goal specifications. However, this even-tuality is currently being met by both conceptual and prac-tical challenges that threaten to slow down the pace of innovation. We argue that two fundamental directions will help evolve the state of self-managing storage sys-tems: (i) a standardized development environment for self-management extensions that also addresses ease of de-ployment, and (ii) a theoretical framework for reason-ing about behavioral properties of individual and collec-tive self-management extensions. We propose Active Block Layer Extensions (ABLE), an operating system infrastruc-ture that aids the development and manages the deployed instances of self-management extensions within the storage stack. ABLE develops a theory behind block layer exten-sions that helps address key questions about overall storage stack behavior, data consistency, and reliability. We exem-plify specific storage self-management solutions that can be built as stackable extensions using ABLE. Our initial expe-rience with ABLE and few block layer extensions that we have been building, leads to believe that the ABLE infras-tructure can substantially simplify the development and de-ployment of robust, self-managing, storage systems. 1