STORAGEDB: Enhancing the Storage Sub-system with DBMS Functionalities

This paper proposes STORAGEDB: a paradigm for im-plementing storage virtualation using databases. It de-scribes details for storing the logical-to-physical mapping information as tables within the database; handling the in-coming I/O requests of the application as database queries; bookkeeping of the I/O operations as database transac-tions. In addition, STORAGEDB uses built-in DBMS fea-tures to support storage virtualization functionalities; as an example we describe how online table space migration can be used to support reallocation of logical disks. Finally, we describe our modifications to a traditional RDBMS imple-mentation, in order to make it light-weight. Improving the performance of a traditional DBMS is critical for the ac-ceptance of STORAGEDB since the performace overheads are considered a primary challenge in replacing existing storage virtualization engines. Our current lightweight RDBMS has a 19 times shorter invocation path length than the original. In comparision to the open-source virtualiza-tion software, namely LVM, the extra cost of STORAGEDB is within 20 % of LVM in trace-driven tests. (unlike STOR-AGEDB, LVM did not have logging overhead). We consider these initial results as the “stepping stone ” in the paradigm of applying databases for storage virtualization. 1