What is a quorum?
A job requires a minimum of two Agents that are able to communicate to form a quorum. A job may have multiple Agents but at least two Agents must be available and connected for replication or synchronization to occur. If the number of connected Agents for drops below two, then that job is said to have lost its quorum.
Quorums apply to File Collaboration, File Replication, and File Synchronization jobs.
How does a job lose its quorum?
A job can lose its quorum due to anything that causes the Agents not to be able to connect to Peer Management Center (via the Broker) or not to be able to communicate in a timely fashion. Communication problems between the Agents and Peer Management Center are typically the cause of quorum loss. Common problems include network issues, manually stopped Agents, stopped VMs, blocked firewall ports after configuration changes. See What causes an Agent to disconnect?
What happens if a job loses its quorum?
When a job loses its quorum, the next event/activity on the remaining connected Agent will cause the job to be stopped. No further processing will occur until a quorum is re-established.
How do I re-establish the quorum?
- Investigate the possible communications issues (application and networking) that may have occurred.
- Confirm network connectivity.
- Verify that the firewall ports used by Peer Management Center are not blocked:
- If using SSL/TLS between Peer Management Center and the disconnected Agent, verify that no firewall is blocking port 61617 from the Agent to Peer Management Center.
- If not using SSL/TLS, verify that no firewall is blocking port 61616 from the Agent to Peer Management Center.
- Try restarting the local PMC job and the Agent on the remote system.
- Connectivity issue during Agent update
- How does the Lock function behave when there is a disconnect between Agents and the PMC and broker?
- HSTS blocks access to the PMC's web interface
- Maximize network throughput
- Throttle bandwidth between the Broker and a remote Agent
- What causes an Agent to disconnect?
- What do the Agent connection statuses mean?
- What firewall settings are needed to enable PeerGFS uploads and download software updates?
- What firewall settings are needed when syncing over FTP?
- What is a quorum and how did I lose it?