Grass Valley iControl V.4.43 User Manual
Page 598
Backup and Redundancy
Configuring and Managing Application Server Redundancy
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Configuring and Managing Application Server Redundancy
There are two ways the role and function of a Main Application Server can switch to its
designated Backup: through an automatic failover (Auto-failover) or through a Manual
Takeover. In either case, you must create a Redundancy Group on the Redundancy
Configuration Form Web page of any Application Server you would like to assign to your
group. After the group’s creation, any further configuration, including adding and removing of
Application Servers, can be accomplished from the Redundancy Configuration Form of any
Application Server belonging to this Redundancy Group.
You can enable or disable the Auto-failover function of individual Application Servers in a
Redundancy Group. With this function enabled, as long as there is a valid, standby Application
Server, configured in a Backup role, a Main Application Server meeting failover criteria
switches automatically to the Backup.
In addition, as long as there is at least one Backup Application Server in standby mode,
operators can perform a Manual Takeover from any Main to any Backup in the Redundancy
Group.
As there are two independent switching mechanisms (Auto-failover and Manual Takeover),
there are system behaviors you should take note of regarding potential conflicts between
them, as follows.
Considerations when Configuring Application Server Redundancy
There are several things we recommend you consider before and during the act of configuring
your Application Server redundancy:
• If there is a performance difference among the Application Server hardware in your
Redundancy Group, make sure the best performing Application Server is the Backup.
See also
For more information about restoring configuration data to an Application Server,
see
Note: To perform Manual Takeovers, you do not need to disable the Auto-failover
function of the Main Application Server.
IMPORTANT: System behavior
In the scenario where two or more Application Servers are configured as a
Redundancy Group for Auto-failover and there is a condition present that, when
detected, will cause an Auto-failover to the Backup, the following system
behaviors result:
•
If a user initiates a Manual Takeover and this is already in progress before the
Backup Heartbeat function triggers an Auto-failover, then the Manual
Takeover occurs and the Auto-failover is suspended.
•
If an Auto-failover is already in progress when a Manual Takeover is
attempted, then the Auto-failover occurs and the Manual Takeover command
is ignored.