Managing Superdome Complexes: A Guide for HP-UX System Administrators

Planning Superdome Conﬁgurations

Rules and Guidelines for Conﬁguring a Complex

Appendix A326

Building a Complex from Scratch

When building a complex from scratch, begin with the largest

partition and proceed to the smallest.

Put the ﬁrst cell of the largest partition in slot 0 of the left CPU cabinet,

then start the next largest partition in the lowest-numbered of the

remaining empty slots, and so on. Systems conﬁgured at the factory are

built according the following algorithm:

• Allocate partitions from largest to smallest.

• When starting a new partition:

1. ﬁll empty cabinets before adding to a partially populated cabinet;

2. within a partially populated cabinet, next ﬁll empty quads (that

is, slots 0-3 or 4-7 in a cabinet);

3. ﬁll remaining slots from left to right by ﬁrst ﬁlling in the

even-numbered slots, then the odd.

Exception: Partitions larger than six cells in a 64-way-capable system

are not built in a simple left-to-right fashion. For example, if you have a

factory-conﬁgured eight-cell partition, you will probably notice that it is

spread across three crossbars, with six cells in one cabinet and two in the

other. A 64-way-capable system has only one link between any two

crossbars (see the Cross-Flex cabling diagram under “Cross-Flex and

U-Turn” on page 315), and conﬁning the eight-cell partition to two

crossbars would overload that link. Testing shows that spreading this

partition across three crossbars results in much better performance.

If you are planning to conﬁgure or reconﬁgure a large partition (seven

cells or more) in a 64-way-capable system, consult your HP Service

Engineer or Customer Engineer for speciﬁc guidance.

Starting-slots for new partitions. The factory chooses starting slots

in the following order, using the lowest priority-number that corresponds

to an empty slot with enough empty slots to the right of it to build the

partition: