HP 3PAR Operating System Software - Manual (Page 248)

Figure 69 One Backup System Failure with SLD Remote Copy
In this example, when SystemB is restored, HP 3PAR Remote Copy transfers data from SystemA to
SystemB and restores synchronous mode remote copy between SystemA and SystemB.
Handling Primary System Failure
If the primary system in an SLD remote-copy configuration fails, the asynchronous-periodic mode
secondary array is the anticipated failover site. SLD operation allows the latest data from the
synchronous-mode secondary array to be pulled over to the asynchronous-periodic mode secondary
array, which then serves data until the primary array is recovered.
248 Disaster Recovery for SLD Configurations