Home > Workload Solutions > SAP > Guides > SAP HANA HCI Guides > SAP HANA Deployments on Dell PowerFlex Hyperconverged Infrastructure > Capacity requirements
If the data that is written to the PowerFlex cluster is configured within a protection domain, it is mirrored on two different physical nodes (SDSs). Therefore, it is necessary to double the estimated capacity that is required for the SAP HANA deployments and add the spare capacity requirement to determine the final capacity requirements. If vSphere VM snapshots or PowerFlex storage snapshots are used, this capacity must also be considered.
In a PowerFlex cluster, spare capacity is reserved for the PowerFlex system to use when recovery from a failure is required. The spare capacity stores rebuilt data after a component failure and cannot be used for storage allocations. The spare capacity must be at least the size of the largest node.