[feature] support the `x.x.x.x:/dbbackup` nfs address.

[acekingke]

Is your feature request related to a problem? Please describe.

Describe the solution you'd like

1. if use x.x.x.x , it use nfs ip address and mount at `/'
2. if use ``x.x.x.x:/yyyit use nfs ip address and mount at/yyy'

Describe alternatives you've considered

Additional context