Flash devices are not mandatory in a StoreVirtual VSA solution.
Each StoreVirtual VSA node can have up to a maximum of 7 virtual/physical data disks attached. *However, a single virtual/physical device can actually consist of multiple SSDs/HDDs connected to a Smart RAID controller that builds one Logical Device on top of the underlying physcial devices this. Therefore a single physical host can have up to 24-26 SFF disks (SSDs or HDDs) mapped to HPE StoreVirtual VSA.
Each StoreVirtual VSA node can have up to a maximum of 50TB of storage attached. The storage capacity can be entirely based on magnetic disks, solid-state disks, or a mix of both disk types.