A Fault Set in PowerFlex requires a minimum of 3 nodes to ensure fault tolerance.

To utilize Fault Sets effectively for their intended purpose (rack-level fault tolerance), the cluster architecture imposes specific minimums.

PowerFlex relies on distributing data copies (Mesh Mirroring). The standard redundancy scheme creates 2 copies of data. To ensure that data remains available even if one entire Fault Set (e.g., an entire rack) fails, the system must be able to distribute the mirrors across different Fault Sets. Consequently, you generally need a minimum of 3 Fault Sets (System requires 3+ Fault Sets to support 2-copy layouts effectively). Since a Fault Set must contain at least one node, the cluster requires a minimum of 3 nodes to support a Fault Set configuration.