The Transactional Activation module ensures synchronization of content between multiple public instances. The module extends the one-subscriber of the Community Edition by providing parallel publishing to up to 10 public instances. Publishing to multiple subscribers is encapsulated in single transaction. This means that if one of the public instances is down, content will not be published to any of them.
Content is published transactionally automatically when the Transactional Activation module is installed. No configuration is required.
Publishing content to all subscribers in a single transaction means that if one of the public instances is down, content will not be published to any of them. The user is notified of the situation in an error message. To resume activation in such case, an administrator has to either bring the affected subscriber back online, disable it, or remove it from the list of subscribers. When they later enable such a subscriber, it is strongly recommended to completely republishing all content to the affected subscriber.
Transactional publishing works the same way for unpublishing. It also works the same way whether publishing is invoked directly or via an approval workflow.
While it is possible to have more than 10 subscribers (public instances), the Transactional Activation module can only publish content to up to 10 subscribers in parallel.