The master device you assign in device groups is the device panorama will poll for user membership and group mapping information. This information is usually not very dynamic as AD groups don't tend to change a lot.There is no HA backup because during the time the master might be offline, panorama will simply not be able to add new groups and group members (old information is maintained until the next refresh)Manually changing the master risks purging the existing cache
The master device you assign in device groups is the device panorama will poll for user membership and group mapping information. This information is usually not very dynamic as AD groups don't tend to change a lot. There is no HA backup because during the time the master might be offline, panorama will simply not be able to add new groups and group members (old information is maintained until the next refresh) Manually changing the master risks purging the existing cache