IBM Global Mailbox - System principles
Global Mailbox solution is designed around some specific availability principles for trading partner connections, user actions, and message processing.
Global Mailbox is designed around the availability requirements for the following tasks:
- Trading partner connections and user actions
- Message processing
Trading partner connections and user actions
Global Mailbox design is governed by the following trading partner connection and user actions:
- A trading partner is connected to a data center based on the location, thus there is always an affinity to the nearest data center.
- Global Mailbox is always available for trading partner actions (upload or download of a file), even when a node or an entire data center is down (planned or unplanned). When a data center goes down, the global load balancer directs trading partner users to another available data center to complete the upload or download of a file.
- Trading partner actions are governed by protocol adapters, which are required for file transfers from and to trading partner users. Trading partners typically interact with a single data center (during normal functioning of the solution or when there is any outage) and their actions do not span across data centers. To upload or download a file when there is an outage, most of the nodes in the local data center must be available. It is not required for most of the nodes in all data centers to be available or be updated about upload or download actions immediately.
Important: If you change the default replication setting (delayed), then for a trading partner action to complete, the available data center must meet other consistency and coordination requirements.
In Global Mailbox, a message is not processed more than one time and the processing status is consistent across data centers. To process a message, the system must be able to read and write from a majority of nodes in all data centers to ensure the processing data is always up-to-date.