Expanse is a Dell integrated compute cluster, with AMD Rome processors, interconnected with Mellanox HDR InfiniBand in a hybrid fat-tree topology. The compute node section of Expanse has a peak performance of 3.373 PF. Full bisection bandwidth is available at rack level (56 compute nodes) with HDR100 connectivity to each node. HDR200 switches are used at the rack level and 3:1 oversubscription cross-rack. Compute nodes feature 1TB of NVMe storage and 256GB of DRAM per node. The system also features 7PB of Lustre based performance storage (140GB/s aggregate), and 5PB of Ceph based object storage.