For example, the B2-3 base configuration PDomain contains three LDoms, but the number of PCIe cards and slots that are available for each LDom in that configuration varies, as described in B2-3 LDom Configuration.
If you want a greater number of free PCIe slots for optional Fiber Channel PCIe cards, you might chose either LDom 1 in the B2-3 configuration PDomain or a different configuration PDomain altogether that offers even larger LDoms. For example, you might find that an extended configuration PDomain works best, where certain LDoms span across two DCUs and therefore would have PCIe slots from both DCUs available for that LDom.
As an example, consider the E2-3 extended configuration PDomain, as described in E2-3 LDom Configuration, which contains three LDoms, like the B2-3 base configuration PDomain. The number of PCIe slots for the second and third LDoms are similar to those of the B2-3 base configuration PDomain. However, the number of PCIe slots for the first LDom is considerably larger in the E2-3 extended configuration PDomain compared to the B2-3 base configuration PDomain.
The following table shows the number of IB HCAs and free PCIe slots that are available for the LDoms in each of those configuration PDomains.