Building smart memories and high-speed cloud services for the internet of things with derecho

Acuerdo: Fast Atomic Broadcast over RDMA

“…In Acuerdo, the replicas leverage these identifiers to efficiently notify each other of received and committed messages, which, thanks to the RDMA FIFO guarantees, implicitly acknowledge their previously received and committed messages. As an added advantage, since subsequent RDMA writes to the same location overwrite earlier values, these replica state updates can always be directed to the same address, simplifying update handling [17].…”

“…As with most quorum based systems, the quorum is "flexible"; the system as a whole does not manage which nodes are in or out but instead simply gathers a minimal number of responses. This design decision stands in contrast to a virtual synchrony model [6,7,9], as used in the Derecho algorithm [16,17], in which the quorum is explicitly managed in response to detected failures or slowdowns. A virtual synchrony scheme will take action if the delay is "bad enough" to merit the cost of reconfiguration.…”

“…Some work fails to take advantage of the FIFO delivery benefits of RDMA [29,38]. Most work adds some waiting on the critical path with dramatic performance consequences: a single delayed message in these systems can halt the entire system's progress [16,17]. Our work is specifically designed to take advantage of the benefits that RDMA can offer, resulting in latencies nearly 2𝑥 faster than prior art while providing competitive bandwidth.…”

Towards Low-Latency Byzantine Agreement Protocols Using RDMA

“…APUS [8] combines RDMA with Paxos and focuses on scalability regarding concurrent connections. Derecho [9] is a C++ library offering replicated crash faulttolerant services, also aiming for RDMA communication in data centers. However, these protocols consider only fail-stop failures; to our knowledge, there is no previous work that assumed Byzantine faults.…”

“…For permissioned blockchain settings, the BFT replicas responsible for consensus can be placed inside a data center without compromising the concept of the blockchain. Few researchers have explored RDMA technology with consensus algorithms so far [7]- [9]; however, all assume a fail-stop model. To our knowledge, no contribution assumed a Byzantine fault model.…”