Asterisk setup with Load balance and failover

We are considering to setup our Asterisk server via 2 datacenters in stead of one, if we should experience technical failures in the future.

We are considering a setup with load balance and failover, but we have heard that with this setup we can risk delays in connections with the communication between the two datacenters.

We have also considered a setup, where we have two identical servers in each datacenter and via a proxy shift to the secondary server, if the primary server fails

But what do you do? Do you have multiple servers in different centers, which you distribute the traffic between, or do you have a primary server and then a secondary server, which takes over, if the primary fails, or how is your setup?