Evaluating Lustre's Metadata Server on a Multi-Socket Platform

With the emergence of multi-core and multi-socket non-uniform memory access (NUMA) platforms in recent years, new software challenges have arisen to use them efficiently. In the field of high performance computing (HPC), parallel programming has always been the key factor to improve applications performance. However, the implications of parallel architectures in the system software has been overlooked until recently. In this work, we examine the implications of such platforms in the performance scalability of the Lustre parallel distributed file system's metadata server (MDS). We run our experiments on a four socket NUMA platform that has 48 cores. We leverage the mdtest benchmark to generate appropriate metadata workloads and include configurations with varying numbers of active cores and mount points. Additionally, we compare Lustre's metadata scalability with the local file systems ext4 and XFS. The results demonstrate that Lustre's metadata performance is limited to a single socket and decreases when more sockets are used. We also observe that the MDS's back-end device is not a limiting factor regarding the performance.