实现基于RDMA的持久内存事务的高效同步镜像
Enabling Efficient RDMA-based Synchronous Mirroring of Persistent Memory Transactions
摘要：
同步镜像（SM）是构建高可用性和容错企业存储系统的标准方法。SM通过维护多个精确的数据副本并将每次更新同步传播到所有副本来确保强大的数据一致性。这种强一致性提供了容错保证和企业系统设计人员梦寐以求的简单编程模型。对于当前的存储设备，SM带来适度的性能开销。这是因为同时执行本地更新和远程更新仅比仅执行本地更新稍微慢一些，这是由于当今系统中对存储的访问的性能相对较慢。然而，新兴的持久存储器和超低延迟网络技术需要仔细重新评估现有的SM技术，因为这些技术与传统技术相比，呈现出根本不同的延迟特性。除此之外，现有的低延迟网络技术，例如远程直接存储器访问（RDMA），提供有限的排序保证，并且不提供SM所需的耐久性保证。为了评估基于RDMA的SM的性能影响，我们开发了一个严格的测试框架，是基于模拟持久内存。我们的测试框架使用了两种不同的工具：（i）可配置的微基准和（ii）WHISPER基准套件的修改版本，其中包括一组常见的云应用程序。使用这个框架，我们发现，最近提出的RDMA原语，如远程提交，提供正确性保证，但没有充分利用RDMA硬件的异步性质。为此，我们提出了新的原语，使高效和正确的SM在RDMA，并使用这些原语开发两种新的技术，提供高性能的SM的持久性存储器。
英文摘要：
Synchronous Mirroring (SM) is a standard approach to building highly-available and fault-tolerant enterprise storage systems. SM ensures strong data consistency by maintaining multiple exact data replicas and synchronously propagating every update to all of them. Such strong consistency provides fault tolerance guarantees and a simple programming model coveted by enterprise system designers. For current storage devices, SM comes at modest performance overheads. This is because performing both local and remote updates simultaneously is only marginally slower than performing just local updates, due to the relatively slow performance of accesses to storage in today's systems. However, emerging persistent memory and ultra-low-latency network technologies necessitate a careful re-evaluation of the existing SM techniques, as these technologies present fundamentally different latency characteristics compared than their traditional counterparts. In addition to that, existing low-latency network technologies, such as Remote Direct Memory Access (RDMA), provide limited ordering guarantees and do not provide durability guarantees necessary for SM. To evaluate the performance implications of RDMA-based SM, we develop a rigorous testing framework that is based on emulated persistent memory. Our testing framework makes use of two different tools: (i) a configurable microbenchmark and (ii) a modified version of the WHISPER benchmark suite, which comprises a set of common cloud applications. Using this framework, we find that recently proposed RDMA primitives, such as remote commit, provide correctness guarantees, but do not take full advantage of the asynchronous nature of RDMA hardware. To this end, we propose new primitives enabling efficient and correct SM over RDMA, and use these primitives to develop two new techniques delivering high-performance SM of persistent memories.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
