As you create and configure rollover ready partitions, the order in which they are used depends on the rollover criteria you set. By default, partitions configured with volume-based criteria are used in the same order they are made ready for rollover. Partitions configured with time-based criteria are used in the order the rollover dates determine.
You can change partition rollover order using the tab on the page.
To change rollover order
In the administration console, right-click a vault store and click Properties.
From the list of ready partitions, select the one whose position you want to change.
Click Move Up or Move down until the partition is in the correct position.
Repeat the previous two steps until the ready partitions are in the correct order.