Deploying an SAP HANA multimode scale-out cluster on FC-connected systems requires the SAP HANA storage connector (fcClient). The storage connector is responsible for mounting and unmounting the persistence (data and log) to the SAP HANA worker nodes.
In addition to mounting the devices, the storage connector also writes SCSI-3 persistent reservations (PRs) to the devices. The Linux sg_persist command initiates the operation, known as I/O fencing, which ensures that only one SAP HANA worker host has simultaneous access to a set of data and log devices.
The SAP HANA default storage connector fcClient is not used when the SAP HANA persistence resides on NAS (NFS) file systems.