The complexity of robust atomic storage

We study the time-complexity of robust atomic read/write storage from fault-prone storage components in asynchronous message-passing systems. Robustness here means wait-free tolerating the largest possible number t of Byzantine storage component failures (optimal resilience) without relying on data authentication. We show that no single-writer multiple-reader (SWMR) robust atomic storage implementation exists if (a) read operations complete in less than four communication round-trips (rounds), and (b) the time-complexity of write operations is constant. More precisely, we present two lower bounds. The first is a read lower bound stating that three rounds of communication are necessary to read from a SWMR robust atomic storage. The second is a write lower bound, showing that Ω(log(t)) write rounds are necessary to read in three rounds from such a storage. Applied to known results, our lower bounds close a fundamental gap: we show that time-optimal robust atomic storage can be obtaine...

• Type: Journal
• Year: 2011
• Where: PODC
• Authors: Dan Dobre, Rachid Guerraoui, Matthias Majuntke, Neeraj Suri, Marko Vukolic
• Keywords: Distributed And Parallel Computing, Fundamental Gap, Optimal Resilience, PODC 2011, Time Complexity