Using a secondary OMS
A secondary OMS server prevents downtime due scheduled maintenance or to a hardware or network failure.
You may choose to have one OMS against which all users and assets authenticate, or you can choose to add a secondary OMS (licensed separately). This ensures that OMS has high availability. When a synchronization occurs between the two OMS servers all configuration settings are compared and replicated. Although not designed for load-balancing, if both servers are up either server may respond to authentication requests or to share filters, protocols, and the like.
You cannot force a synchronization between the primary and secondary OMS, but every 10 seconds any change on the primary server is sent to the secondary server. Likewise, any change on the secondary server is sent to the primary server every 10 seconds. Every 10 minutes the primary server compares configuration settings with the secondary server. The primary server compares the settings it receives against its own to determine whether the settings are identical. If they are not identical, then the primary server replicates its complete configuration to the secondary server. This overwrites any changes made on the secondary server not approved by the primary server. If for some reason synchronization fails, it is reattempted in 10 seconds or at most in 10 minutes when the primary server requests configuration settings from the secondary server.
The secondary server is always running and live. It is always considered the secondary server even if the primary server is unavailable for any reason and regardless for how long the primary server is unavailable. The secondary server continues fulfilling the duties of the primary server until the primary server is available.
Under most circumstances, you would only want to make changes on the primary server so that the primary server can push its settings to the secondary server. Only when the primary server is unavailable and you need to make changes do we recommend that you make changes on the secondary server. When the primary server comes online any configuration changes made on the secondary server during this period will be overwritten.
OMS never automatically promotes or changes the primary or secondary role of your servers. To avoid your changes that you made on the secondary server from being overwritten, make the secondary server the primary server, bring the former-primary online and make it secondary. The new primary will then push its settings to the former primary/now secondary. After you are certain configuration settings have synchronized, you can switch their roles back to their original settings.
 
Figure 8: Example of failover operation
Conceptual image of failover operationConceptual image of failover operation
 
Defining a failover OMS
Using a failover server ensures the least amount of disruption and allows users to stay productive if there is a network or hardware issue.
Follow these steps to configure OMS to use two servers to maintain maximum uptime.
1. Starting in the dashboard, click System > Update.
2. In the System Settings pane, click Failover.
3. Complete the fields. Use the information in Failover settings for details.
4. Click the accept icon .
 
The failover server is created when the Failover server saved notification appears on the screen.
 
Failover settings
The failover settings control whether a failover server is used. Use this information to configure a failover server.
 
Enable failover mode
If selected, failover mode is enabled between the primary and secondary servers.
View 'Connection to the failover server' to ensure the primary and secondary servers are communicating.
Set this server as primary
If selected, this OMS server is the primary server in a failover configuration. Otherwise, it is the secondary or failover server.
Only v17 or newer assets will report a value.
IP address/DNS of the other failover server
The host address of the other OMS server.
Valid Input: Valid addresses include IPv4, IPv6, or DNS name.
Maximum days to keep unpropagated configuration changes
Sets the maximum number of days without connectivity to a primary server before configuration changes stop accumulating and replicating to the secondary server. If this happens, the primary server replicates its complete configuration to the secondary server after connectivity is re-established.
Any configuration changes made on the secondary server during this period will be overwritten.
Connection to the failover server
A read-only field.
The network connection status between the primary and secondary server.
 
Becoming a primary/secondary OMS
Prerequisite(s):  
Ensure you have defined the secondary OMS. See Defining a failover OMS.
 
If you have two OMS systems, follow these steps to switch roles of the OMS systems. These instructions assume you want to promote the secondary server to the primary server.
1. Starting in the dashboard, click System > Update.
2. In the System Settings pane, click Failover.
3. On the primary server, clear Set this server as primary.
4. On the secondary server, select Set this server as primary.
5. Click the accept icon .
 
The OMS systems communicate and exchange roles.