Simurgh

Abstract

The availability of non-volatile main memory (NVMM) has started a new era for storage systems and NVMM specific file systems can support extremely high data and metadata rates, which are required by many HPC and data-intensive applications. Scaling metadata performance within NVMM file systems is nevertheless often restricted by the Linux kernel storage stack, while simply moving metadata management to the user space can compromise security or flexibility.This paper introduces Simurgh, a hardware-assisted user space file system with decentralized metadata management that allows secure metadata updates from within user space. Simurgh guarantees consistency, durability, and ordering of updates without sacrificing scalability. Security is enforced by only allowing NVMM access from protected user space functions, which can be implemented through two proposed instructions. Comparisons with other NVMM file systems show that Simurgh improves metadata performance up to 18x and application performance up to 89% compared to the second-fastest file system. CCS CONCEPTS• Information systems → Storage class memory; Phase change memory; • Software and its engineering → File systems management.

Anisotropic behavior in the lithiation of a silicon nanopillar

“…In cases of SATA/IDE, the target system employs a hardware controller (i.e., disk controller) to manage their storage interface protocol, so the interface driver usually handles I/O interrupt or system memory management. In contrast, in the case of NVMe, a kernel module (NVMe driver) [11], [54], [55] Arrakis [14], [15], [16] Ishiguro et al [29] Aerie [17] RUMA [56] NVMeDirect [12] Moneta-D [20] Direct-FUSE [18] Strata [30] Breeze [57] Simurgh [25] XFUSE [58] SplitFS [21] HyCache [59] Quill [26] Son et al [60], [61] ZoFS [22] Davram [62] vNVML [27], [28] EvFS [19] Kuco [63] DLFS [64] URFS [65] UMFS [31] DevFS [23] CrossFS [24] FSP [32] directly accesses the PCIe bus over a memory mapped I/O and issues the request to the target SSD by composing an nvme_rw_command.…”

“…Moti et al [25] designs a user-space file system named Simurgh, which bases its core design on virtualizing NVM. Considering that NVM achieves similar performance to DRAM and is byte-addressable, Simurgh directly maps NVM into the address space of each application without employing DRAM to cache data and metadata from NVM.…”

“…Specifically, many research [11], [13] concentrate on implementing user-space storage driver or I/O framework in order to grant the user applications full access to the underlying storage resources. Other prior studies [14], [15], [16], [20], [25], [26], [27], [28] consider to decouple the memory management and the system software such that the address translation and boundary check can be served directly from the user space. Furthermore, there are also multiple new designs of file systems [17], [18], [19], [21], [22], [23], [24], [29], [30], [31], [32] to minimize the involvement of kernel in the file accesses.…”