HP StorageWorks XP Remote Web Console Software - Manual (Page 10)

Figure 2 Cascade Pairs
The first cascade layer (L1) is the original XP Business Copy pair. In case of cascaded pairs, the
P-VOL of the L1 pair is called root volume, and the S-VOL is called node volume. The P-VOL of the
second cascade layer (L2) is the node volume of L1 pair, and the S-VOL of the L2 pair is called
leaf volume. As shown in
Figure 2 (page 10) , this layering scheme allows you to create up to nine
10 About XP Business Copy Operations