High availability cluster

You can connect three IBM Storage Fusion HCI System racks to create a single large OpenShift® Container Platform and IBM Spectrum Scale ECE cluster.

For example, a three-rack cluster can have up to 3,072 (1,024 x 3) physical cores. These multiple side-by-side (adjacent) appliances act as a single unit and hosts a single storage and OpenShift Container Platform cluster. Here, the control plane nodes are spread across these multiple IBM Storage Fusion HCI System racks. To achieve high availability, 1 control node (Rack Unit 2) is available in each of these three racks so even when one rack goes down, the cluster stays available.

The components in each of the three racks are the same as a single rack. For component details and hardware configuration, see Hardware overview of a single rack.

Prerequisites:
  • Order three similar racks from IBM factory. Ensure you have 3 racks having a minimum of 6 nodes per rack.
  • Order two spine switches (MTM 9155-S01) from IBM and the cables to connect the racks to the spine switches. For the spine switch installation instructions, contact IBM Support. You must order the spine switches from IBM. You may order the cables from IBM or provide the cables yourself. Determine the length of the required cables based on the proximity of the racks to the spine switches.
  • Ensure that the number of NVMe drives are uniform across storage nodes.