A customer observed that devices where as duplicates in DCR - with the DNS name and the IP address. Currently we assume that this issue occures when the DNS server is not available and a discovery cycle runs. Thus the devices' IP address could not be resolved to a name and it will further be processed by its IP address. I know there is CSCsv65933 which affects the update of the DCRDisplay Name in CS 3.2 but the available patch from TAC is not installed on the system.
I cannot find any documentation about the behaviour of CSDiscovery when DNS is temporarily not available and the following settings for discovery are made:
use DCR as seed
Preferred DCR Display Name: FQDN
update DCR Display Name: yes
preferred Mgmt IP: Resolve by Name
So what happens if a device is in DCR with its FQDN and the next discovery cycle ths DNS server is not available. Will it be added into DCR with its IP or will the discovery process still find out that it is yet in DCR. And does this dependents on the way how the device will be picked up by the discovery process: as a seed from DCR or as a CDP neighbor in one of the discovery threads?