Minuet: Rethinking Concurrency Control in Storage Area Networks.
ABSTRACT Clustered applications in storage area networks (SANs), widely adopted in enterprise datacenters, have tradition- ally relied on distributed locking protocols to coordi- nate concurrent access to shared storage devices. We examine the semantics of traditional lock services for SAN environments and ask whether they are sufficient to guarantee data safety at the application level. We ar- gue that a traditional lock service design that enforces strict mutual exclusion via a globally-consistent view of locking state is neither sufficient nor strictly necessary to ensure application-level correctness in the presence of asynchrony and failures. We also argue that in many cases, strongly-consistent locking imposes an additional and unnecessary constraint on application availability. Armed with these observations, we develop a set of novel concurrency control and recovery protocols for clustered SAN applications that achieve safety and liveness in the face of arbitrary asynchrony, crash failures, and network partitions. Finally, we present and evaluate Minuet- a new synchronization primitive based on these protocols that can serve as a foundational building block for safe and highly-available SAN applications.
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ABSTRACT: Caching introduces the overhead and complexity of ensuring consistency, reducing some of its performance benefits. In a distributed system, caching must deal with the additional complications of communication and host failures. Leases are proposed as a time-based mechanism that provides efficient consistent access to cached data in distributed systems. Non-Byzantine failures affect performance, not correctness, with their effect minimized by short leases. An analytic model and an evaluation for file access in the V system show that leases of short duration provide good performance. The impact of leases on performance grows more significant in systems of larger scale and higher processor performance.ACM SIGOPS Operating Systems Review 01/1989; 23(5):202-210.
Article: The vax/vms distributed lock managerDigital Technical Journal - DTJ. 01/1987;
- ACM Computing Surveys. 01/1990; 22:299--319.