The server has one or two disk backplanes depending on the number of storage drives installed. On servers with four or fewer storage drives, only one disk backplane is needed. Servers with five or more storage drives require two disk backplanes. The following figure shows a configuration with two disk backplanes, DBP0 and DBP1. Storage drives 0-3 plug into DBP0. Storage drives 4-7 plug into DBP1.
Figure 66 Disk Backplane Configurations