About RHSP and VSS
RHSP exposes the Edge through iSCSI to the Windows server as a snapshot provider. Only use RHSP when an iSCSI LUN is mounted on Windows through the Windows initiator. The process begins when you (or a backup script) request a snapshot through the VSS on the Windows server.
The default port through which the Windows server communicates with the Edge appliance is 4000.
1. VSS directs all backup-aware applications to flush their I/O operations and to freeze.
2. VSS directs RHSP to take a snapshot.
3. RHSP forwards the command to the Edge.
4. The Edge exposes a snapshot to the Windows server.
5. The Edge and Core commit all pending write operations to the storage array.
6. The Edge takes the snapshot against the storage array.