A Method to Adapt Storage Protocol Stack Using Custom File Metadata to Commodity Linux Servers
Takayuki Fukatani, Atsushi Sutoh, Takahiro Nakano · International Journal of Smart Computing and Artificial Intelligence · 2018
Storage vendors have had difficulty adapting their proprietary protocol stacks to commodity servers.Despite large development effort, many proprietary protocol stacks can be used only on the specialized storage appliances because they depend on specialized hardware or software.Most of these protocol stacks use original filesystems to store custom file metadata that contain the protocol specific metadata to comply with the protocol specifications.In this study, we propose a new metadata management module named the protocol metadata module (PMM) that enables the custom file metadata to be used on commodity Linux servers.The PMM uses a portable operating system interface (POSIX)-based Linux interface to store the custom file metadata in Linux filesystems so that the protocol stacks can use the custom file metadata without the specialized hardware or software.The PMM enables the protocol stacks using the custom file metadata to offer the protocol functions on commodity Linux servers.We applied our developed PMM to the protocol stack of our storage appliance to verify its concept.Our evaluation results show that the PMM increases the protocol function coverage from 75.0% to 96.7% on Linux servers while suppressing the access performance degradation to at most 8% in the typical file server workloads.