You can configure the SMS to operate in an active-passive, high availability (HA)
cluster, increasing availability of the SMS when an unexpected event causes the primary
SMS to fail or become inaccessible. The SMS HA cluster consists of two nodes, a primary
and a secondary. If the primary SMS becomes unavailable, the secondary SMS becomes
active.
In the Admin workspace, select
High Availability in the navigation pane to display the Admin (High Availability) screen. From this
screen you can configure and adjust the SMS HA settings, synchronize the two nodes,
and monitor the HA cluster status.
Learn more.
Synchronization
During initial configuration, the SMS synchronizes the database from the active SMS
to the passive SMS. To keep the passive SMS current, the active SMS replicates critical
SMS data to the passive SMS.
Failover
The process of promoting a passive SMS server to an active SMS server is called failover.
A failover occurs when the primary SMS server experiences a fault or is taken offline
for maintenance. You can also manually failover the cluster and swap roles between
the active and passive SMS servers.
Learn more.
Heartbeat
When the cluster is operating in a normal state, the passive server periodically sends
a heartbeat signal to the active server.
If the passive server is unable to obtain a response from the active server, the passive
server assumes the active server is unavailable and initiates a failover process.
The total heartbeat timeout and the mitigation timeout are configurable fields that
determine the total time the passive SMS spends to recover from a heartbeat failure.
Learn more.
Network configuration
You can configure SMS HA to send the heartbeat over one of two possible network configurations.
SMS HA can send the heartbeat over the same public network that the SMS uses to communicate
to its clients and managed devices. Alternatively, you can instruct the SMS to send
the heartbeat over a private, intra-cluster Ethernet network. If you use an intra-cluster
network, the replication activity occurs over this private network, removing the traffic
from the public network.
If you configure SMS HA to use the private network, your configuration also has built-in
redundancy. If the heartbeat signal does not make it through the private network,
the SMS attempts to communicate the heartbeat through the public network before initiating
a failover. To make use of an intra-cluster network, connect an Ethernet crossover
cable between the two cluster nodes and configure SMS HA to use a primary and secondary
network configuration.