A sub pool is another SiteBacker/Traffic Controller pool that you can add to a primary pool. A sub pool has its own records, record probes, and pool probes. A sub pool provides another backup and load balancing choice to SiteBacker/Traffic Controller.
A primary pool can have multiple sub pools, and a pool can be a sub pool for multiple primary pools.
A sub pool is equivalent to a pool record from the perspective of the primary pool and uses the same rules to determine whether to serve a record or a sub pool. If you query the primary pool’s name, you will receive all active records in the primary pool and, as well as if the sub pool is active for the primary pool, all records in the sub pool. However, if you query the sub pool’s name, you receive only the sub pool’s active records.
A sub pool is equivalent to its set of pool records from the perspective of the DNS (the resolver processes sub pool records as aliases for a query). For example, when a sub pool is active in a primary pool, SiteBacker serves any active sub pool records in addition to any other active records and sub pools in the primary pool, but the sub pool counts as one server, just like any pool record, when the primary pool calculates its maximum active servers.
Traffic Controller records have assigned weight values. If a Traffic Controller pool is an active sub pool, the application evaluates the weight of each record and distributes the traffic accordingly. For example, assume three weighted records in a primary pool: Primary1 (40%), Primary2 (30%) and Primary3 (30%), and two weighted records in a sub pool: Sub1 (60%) and Sub2 (40%). If the sub pool’s Sub1 is an active record, 60% of the traffic would go to that record’s server, with the remaining traffic distributed to other active records, depending on record priority.
The following example displays a Directional pool with two SiteBacker sub pools within the pool itself. The second example displays the sub pools having their own entries outside of the Directional pool.
How to Add a Sub Pool
To add a sub pool to an existing Pool:
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Edit the primary pool (the one that you want to add a sub pool into).
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Click the Add Record button.
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In the Points To field, provide the sub pool name that you want to add.
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The pool you are using as the sub pool must already be created in your domain.
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Complete the rest of the required fields that are specific to the primary pool type.
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Click Save.
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In the Record list for the pool, your sub pool will now appear, and the record type will display the pool type.
