Planning Superdome Configurations

Planning Superdome Configurations
Rules and Guidelines for Configuring a Complex
Chapter 1 53
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, as on line 21 of the table on page 52.
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 39), 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.