What is a quorum server and how does it help my HA cluster?
Applicable Products
- QuTS hero h5.3.0 or later
- High Availability Manager
Scenario
In a high-availability (HA) cluster, if the network connection between the two nodes is interrupted, they may no longer be able to detect each other's status. This can lead to a split-brain condition, where both nodes take over the active node role, which may result in inconsistent data between the two nodes and service disruption.
Definition and Benefits
To reduce the risk of split-brain, you can configure a quorum server for your HA cluster.
A quorum server is a third-party arbitrator that continually monitors the nodes of your cluster. When the two nodes cannot detect each other but are still connected to the quorum server, the cluster can query the quorum server to check the status of each node. This not only helps prevent both devices from taking over the active node role at the same time, but also increases judgment and timing accuracy in failovers and switchovers.
In summary, the benefits of a quorum server include the following:
- Prevents split-brain
- Improves decision and timing accuracy in failovers and switchovers
- Enhances overall system stability
Configuration
You can configure a quorum server for your HA cluster by going to High Availability Manager > Settings > Failover Policy > Quorum Server. You can simply use a DNS server or network gateway without installing any additional utilities.
For details, see Configuring a quorum server.
