IBM 8408-44E Site And Hardware Planning page 157

When attaching only hard disk drives, it is also possible to cascade a second disk expansion drawer off two out of
the three drawers for a maximum of five disk expansion drawers per adapter. See Figure 62 on page 131.
Notes:
v Disk expansion drawers can be cascaded only one level deep.
v The X cable must be routed along the right side of the rack frame.
v The X cable must be attached to the same numbered port on all adapters.
v Any multi-initiator configuration with FC 5904, FC 5906, and FC 5908 adapters require an AA cable for connecting
the two adapters with each other.
Figure 72. Two PCI-X DDR 1.5 GB cache SAS RAID adapters to disk expansion drawers in a multi-initiator HA raid
configuration
Two RAID SAS adapters with HD connectors to disk expansion drawer in a
multi-initiator high availability (HA) mode
Figure 73 on page 142, Figure 74 on page 143, and Figure 75 on page 144 illustrate connecting two SAS
RAID adapters with HD connectors to one, two, or three disk expansion drawers in a multi-initiator HA
mode.
Figure 76 on page 145 illustrates connecting two pair of SAS RAID adapters with HD connectors to one
disk expansion drawer in a multi-initiator HA mode.
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Site and hardware planning