HA over distance eg fibre?

any of these should provide what you want. 1000BASE-LX Single-mode fiber 5 km 1000BASE-LH Single-mode fiber using 1310 nm wavelength 10 km 1000BASE-ZX Single-mode fiber at 1550 nm wavelength ~ 70 km 1000BASE-LX10 Single-mode fiber using 1310 nm wavelength 10 km 1000BASE-BX10 Single-mode fiber, over single-strand fiber 10 km

I have two (2) FG310B approx. 6km distantce via fiber / LAN. No problems so far. Just upgraded the OS of the cluster, without any problem, upgrade was one after the other so almost no downtime (guess 25 pings (seconds) in total due to failovers).

I have done this at a number of sites. It works well. Ensure that the latency between the sites is acceptable before attempting this. Fiber, as a medium, is fast. However, the cumulative latency caused by the various types of delay along the path may not be acceptable for your requirement. Also, I have implemented QoS on heartbeat traffic, where members of the cluster were separated by miles of fiber AND the heartbeat was sharing the same physical path as the regular traffic. my two cents. pete

Ah thanks guy' s for the responses will move forward with confidence

what' s the max latency before you think you would run into problems?

what' s the max latency before you think you would run into problems?

200ms