To use Composite Dynamic Active/Active you need to have a Composite Active/Active cluster deployed, then it is simply a case of specifying the required affinity within the connectors.
For the purpose of this example we will assume we have two clusters alpha and
beta. Each cluster will have two connectors and it is desired that the alpha
cluster be the primary write destination.
Within the configuration for the connectors, add the following:
connector-write-affinity=alpha,beta
This will have the effect of setting the write affinity to the alpha cluster primarily on both
alpha and beta clusters as follows:
alpha cluster will get both read and write affinity to alpha
beta cluster will get write affinity to alpha, but maintain
read affinity to beta
In the case of the alpha cluster failing, the writes will failover and redirect to the
beta cluster.
After recovering a failed site
As outlined above, if the site that has write affinity fails, read-write traffic will failover to another site based on the affinity rules configured. Following recovery of the site that is configured as the primary write site, new connections will folow the write affinity rules, whereas existing connections will remain on the site that was promoted after failover.
To maintain data-integrity and to ensure writes continue to only be directed to a single site, it is therefore essential to also enable the following tpm property:
--connector-reset-when-affinity-back=true
With this enabled, following recovery of the primary write site, all connections (new and old) will revert to the original, intended, cluster configured with primary write affinity.