For Distributed Consistency Groups in a Dell RecoverPoint environment, the minimum size required for each journal volume is 40 GB. This is the minimum per copy, which can be a single LUN or multiple LUNs that add up to at least 40 GB1.

The size of the journal is determined by the write change rate of what is being replicated and the protection window required per Consistency Group. A general rule of thumb is about 15-20% of the total amount of data being replicated. For example, if a Distributed Consistency Group (DCG) has production server LUNs totaling 500 GB, then the journal per copy would be about 100 GB following this rule1.

It's important to note that while 40 GB is the minimum, the actual size may need to be larger depending on the specific requirements and write change rate of the environment. The journal size should be sufficient to handle the data changes and provide the necessary protection window1.