Is it OK to place a secondary fault tolerant SpectroSERVER system in a different subnet and/or datacenter and/or physical location?
Placing a secondary fault tolerant SpectroSERVER in a different subnet and/or datacenter will work fine. It is actually a good idea to have the secondary SpectroSERVER on a different subnet and location than the primary.
That way, they each have different perspectives on the network. If a switch located upstream of the primary SS goes down, the secondary SpectroSERVER may still be able to see the network when taking over primary management.
Also, if there is an outage (power, communications), the secondary SpectroSERVER will less likely be affected since it is in a separate location.
NOTE: If there is a firewall between the primary and secondary SpectroSERVER, specific ports are required to be open between the primary and secondary SpectroSERVER systems and the OneClick and secondary Spectroserver systems in order for Fault Tolerance to work. Reference chapter 3 "Communication Across Firewalls in the Distributed SpectroSERVER Environment" in the "Distributed SpectroSERVER Administrator Guide" for Spectrum 9.4 and below and the "Communication Across Firewalls" section in the Spectrum 10.x documentation for a list of ports that will need to be opened.
ADDITIONAL INFORMATION: For more information about setting up a Distributed SpectroSERVER environment, please reference the "Distributed SpectroSERVER Administrator Guide" for Spectrum 9.4 and below and the "Distributed SpectroSERVER Administration" section in the Spectrum 10.x document.