A detection module selects logically adjacent first and second control areas of a cluster. The detection module further determines that the first and second control areas satisfy a migration test wherein the first control area has free space exceeding a free threshold, the free space is at least equal to a space requirement for each second control area control interval, and the second control area has fewer control intervals than a control interval threshold. In addition, a copy module copies each second control area control interval to the first control area in response to determining that the first and second control areas satisfy the migration test.