N-to-M redundancy
Setup
The redundancy group contains one or more active nodes and one or more backup (inactive) nodes. In the group, you can have the same number of active and backup nodes, or more active nodes, or more backup nodes.
In one redundancy group, all the active nodes share the backup nodes.
This diagram is an example of an N-to-M redundancy group for Elemental Live nodes. The same design applies to Elemental Statmux nodes.
What happens in a
failure
If an active Elemental Live node fails, Conductor Live automatically moves both the active and idle channels to a backup node, then starts all the active channels. There is a slight delay while the restart occurs.
If an active Elemental Statmux node fails, Conductor Live automatically moves all the active and idle MPTSes to a backup node, then starts all the active MPTSes. There is a slight delay while the restart occurs. In addition, Conductor Live ensures that the Elemental Live nodes send to the new Elemental Statmux node.
There is a delay while the backup node starts up because Conductor Live must copy the data from the failed node to the backup node. During the delay, there is no output for the affected channels or MPTSes.
This diagram illustrates the change in the group after one node fails. This diagram is for Elemental Live but the same pattern applies to Elemental Statmux.
Considerations
-
You must consider the capabilities of the different nodes in the redundancy group. For example, think about the repercussions if you have a backup node that isn't as powerful as the nodes that are usually your active nodes. Think about whether you want to take the risk of having less powerful nodes as backups.
Also consider how you will handle failure of a node that has SDI cards installed. Ideally, there will be a backup node with the same card configuration, espeically if your deployment includes a router handling the SDI input. You might want to consider organizing nodes that have SDI cards in their own redundancy group.
-
You should have a policy in place for handling node failure. Decide whether you will immediately try to get the failed node back into production.
-
Keep in mind that it is possible to have so many nodes in a failed state that you have no backup nodes in the redundancy group.
