Can one cisco Wireless controller act as a backup virtually

[Rajvendra pratap singh]

Hello Folks 

I am not sure it could possible or not but below is the my query regarding cisco wireless controller please assist and guide me . 

Query 
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Is it possible that one wireless controller act as a secondary wireless controller virtually  , or is there any other way please assist .

[Flavio Miranda]

Hi

 it is possible for N+1. Not possible with HA SSO.

 HA SSO the join on the primary wlc and if the prinary fail de secondary take over with zero network downtime.

 N+1 you configure Primary and secondary wlc on the AP. There will be downtime if primary fail.

[Rich R]

You didn't mention what model of WLC or software version but anyway:
Read https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-7/High_Availability_DG.html for AireOS
Read https://www.cisco.com/c/en/us/td/docs/wireless/controller/9800/17-9/config-guide/b_wl_17_9_cg/m_vewlc_high_availability.html for 9800.
And see the High Availability section of best practices guide (below).  N+1 is still the same for 9800.