Negative Effects of Split-Brain Mode in Cisco Utility Connection Servers

AC.

When two Cisco Unity Connection servers in a cluster are in split-brain mode, they are not able to communicate and function as a cohesive unit. This can result in a number of negative effects, including lost or inaccessible messages, out-of-sync message waiting lights, and corrupted databases.

Once the network issue is corrected and the two servers are able to communicate again, there may still be negative effects that need to be addressed. The two statements that describe negative effects of this event are:

A. A user calling in to check their voicemail during the recovery may be informed that their messages are not available. This means that during the split-brain mode, messages that were left on one server may not have been replicated to the other server, and therefore may not be available to users during the recovery period. This can be frustrating for users and may require additional troubleshooting and messaging to keep them informed.

B. Message waiting lights can become out of sync after the split-brain recovery, forcing the administrator to run an MWI Synchronization. Message waiting lights (MWI) indicate whether a user has new messages waiting for them, and they should be in sync across all servers in a cluster. When two servers are in split-brain mode, the MWI lights may become out of sync, meaning that users may not see accurate MWI indications. This requires the administrator to run an MWI synchronization to ensure that all lights are in sync across the cluster.

The other answer choices are either incorrect or partially correct but do not fully describe the negative effects of split-brain mode and recovery.

C. The replication between the nodes becomes defunct, requiring the administrator to run utils cuc cluster activate to re-establish intracluster communication. This answer is partially correct, but it does not fully describe the negative effects of split-brain mode and recovery. While it is true that replication between the nodes becomes defunct during split-brain mode, running "utils cuc cluster activate" is not the only step required to re-establish intracluster communication. Additionally, this step does not fully address the negative effects of split-brain mode and recovery.

D. A message left on the subscriber server during the outage may be lost during the cluster recovery. This answer is partially correct, but it does not fully describe the negative effects of split-brain mode and recovery. While it is true that messages left on the subscriber server during the outage may be lost, this is not the only negative effect of split-brain mode and recovery.

E. The replication between the nodes becomes defunct, requiring the administrator to run utils cuc cluster renegotiate to re-establish intracluster communication. This answer is similar to answer choice C, but it is not fully correct. While it is true that replication between the nodes becomes defunct during split-brain mode and that intracluster communication needs to be re-established, running "utils cuc cluster renegotiate" is not the only step required to address the negative effects of split-brain mode and recovery.

F. The Unity Connection Database can become corrupted, causing the need to reinstall the subscriber server. This answer is incorrect. While it is possible for the Unity Connection Database to become corrupted during split-brain mode and recovery, it is not a guaranteed or necessary outcome. Additionally, even if the database does become corrupted, reinstalling the subscriber server may not be the only solution or the best solution for addressing the issue.