Dell PowerEdge FN I/O Module Configuration Guide 9.10(0.0)

By restoring the settings saved in NVS, the VLT ports come up quicker on the primary VLT node and traffic disruption is reduced. The delay in restoring the VLT LAG parameters is reduced (90 seconds by default) on the secondary VLT peer node before it becomes operational. This makes sure that the configuration settings of the primary VLT node are synchronized with the secondary VLT peer node before the secondary VLT mode is up. The traffic outage is less than 200 millisconds during the restart or switchover of the VLT peer nodes from primary to secondary.