High Availability Storage System Based on Two-Level Metadata Management

Generally storage devices only administrate the mapping of logical data space to local physical space while unknowing other information related to data objects. Network or metadata service failure will disable the system, although the data is still on devices intact and correct. Utilizing the redundant computing ability of storage devices, the object interface makes it possible to assist the MDS for metadata services to improve the availability of the system. Though extended attributes of the object interface and computing resource, the management of the object allocation, and local metadata service are enabled in active object storage devices (A-OSD). Based on A-OSDs, a distributed high availability storage system (HASS) characterized by two-level metadata management can be built to achieve higher availability while maintaining good performance. Experiments indicate under the same environment, compared with Lustre, HASS has better write performance and similar read performance besides the potential high availability.