In high-performance computing (HPC), data and metadata are stored on special server nodes and client applications access the servers’ data and metadata through a network, which induces network latencies and resource contention. These server nodes are typically equipped with (slow) magnetic disks, while the client nodes store temporary data on fast SSDs or even on non-volatile main memory (NVMM). Therefore, the full potential of parallel file systems can only be reached if fast client side storage devices are included into the overall storage architecture. In this article, we propose an NVMM-based hierarchical persistent client cache for the Lustre file system (NVMM-LPCC for short). NVMM-LPCC implements two caching modes: a read and write mode (RW-NVMM-LPCC for short) and a read only mode (RO-NVMM-LPCC for short). NVMM-LPCC integrates with the Lustre Hierarchical Storage Management (HSM) solution and the Lustre layout lock mechanism to provide consistent persistent caching services for I/O applications running on client nodes, meanwhile maintaining a global unified namespace of the entire Lustre file system. The evaluation results presented in this article show that NVMM-LPCC can increase the average read throughput by up to 35.80 times and the average write throughput by up to 9.83 times compared with the native Lustre system, while providing excellent scalability.

中文翻译：

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Lustre 的面向 NVMM 的分层持久客户端缓存

在高性能计算 (HPC) 中，数据和元数据存储在特殊的服务器节点上，客户端应用程序通过网络访问服务器的数据和元数据，这会导致网络延迟和资源争用。这些服务器节点通常配备（慢速）磁盘，而客户端节点将临时数据存储在快速 SSD 甚至非易失性主存储器 (NVMM) 上。因此，只有将快速客户端存储设备包含在整体存储架构中，才能充分发挥并行文件系统的潜力。在本文中，我们为 Lustre 文件系统（简称 NVMM-LPCC）提出了一种基于 NVMM 的分层持久客户端缓存。NVMM-LPCC实现了两种缓存模式：读写模式（简称RW-NVMM-LPCC）和只读模式（简称RO-NVMM-LPCC）。NVMM-LPCC 与 Lustre 分层存储管理 (HSM) 解决方案和 Lustre 布局锁定机制相集成，为运行在客户端节点上的 I/O 应用程序提供一致的持久缓存服务，同时维护整个 Lustre 文件系统的全局统一命名空间。本文给出的评估结果表明，与原生 Lustre 系统相比，NVMM-LPCC 可以将平均读取吞吐量提高高达 35.80 倍，将平均写入吞吐量提高高达 9.83 倍，同时提供出色的可扩展性。