7.4.6 - High Availability Clusters

Flashcards about High Availability Clusters

High Availability Clusters

Allows multiple redundant processing nodes that share data with one another to accept connections. If one node fails, connections failover to a working node. To clients, it appears as a single server.

Virtual IP

The public IP used to access a service that is shared between two instances in a cluster.

Common Address Redundancy Protocol (CARP)

Enables the active node to "own" the virtual IP and respond to connections, using a heartbeat mechanism for failover.

Active-Passive Clustering

One node is actively processing connections while the other is on standby, ready to take over if the active node fails. Advantage: Performance is not affected during failover.

Active-Active Clustering

Both nodes are processing connections concurrently, maximizing hardware capacity. Disadvantage: Performance degradation can occur during failover due to the increased workload on the remaining node.

N+1 and N+M configurations

Provisioning fewer passive nodes than active nodes to reduce costs in an active-passive configuration.

Redundancy Protocol (e.g., CARP)

What type of protocol runs on the private connection between instances in a high availability cluster to enable the active node to "own" the virtual IP and respond to connections?

Performance is not adversely affected during failover

What is the main advantage of active/passive configurations in high availability clusters?

Active-Active Clustering

In what type of clustering configuration: the workload of the failed node is immediately and transparently shifted onto the remaining node, leading to potential performance degradation?