Expansion unit

You can add expansion units to many of the models to support additional features and devices. If you want to create logical partitions on your server, you must add an expansion unit that contains the additional hardware that you need for each logical partition.

Some expansion units can support only disk units (storage expansion unit), while others can support various hardware (system expansion unit). Expansion units generally contain one or more system I/O buses with various I/O devices.

If you assign more than 144 I/O slots to an AIX® or Linux logical partition, ensure that the boot device for the logical partition is within the first 144 slots that are assigned to the logical partition. Also ensure that any PCIe3 2-Port 40GbE NIC RoCE QSFP+ Adapter (FC EC3A or FC EC3B) is within the first 144 slots. You can view the devices that are assigned to the first 144 slots of a logical partition by viewing the partition properties of the logical partition. Select the Hardware tab, then select the I/O tab, and then click the Bus column of the table to sort the devices in ascending order.