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

Planning Superdome Conﬁgurations

Building Blocks and Deﬁnitions

Appendix A 307

Processors Each cell contains four processors. All the processors in the

same partition must be of the same type (the partition will not boot if

they are not). At ﬁrst release, the only processor type available is

PA-8600.

Instant Capacity on Demand (iCOD) All cells are delivered with four

processors, but you pay only for the processors you use. For example, a cell

ordered with two active processors will be delivered with two active and two

inactive processors. If and when you need additional capacity, you can use the

Partition Manager (parmgr) to turn on one or both of the inactive processors, and

HP will bill you accordingly.

NOTE iCOD is a separately orderable product which is not available with the earliest

Superdome shipments; those systems use a different method for turning on

inactive processors. Contact your HP Sales Representative for more information.

Order for Activating Processors. The algorithm the HP tools use to activate new

processors is:

1. There must be at least one active CPU per cell.

2. CPUs are activated round-robin across cells within a partition (that is, ﬁrst

processor 0 in each cell, then processor 3 in each cell, and so on following rule

3). This means that the number of active processors per cell will differ by at

most one across the partition.

3. CPUs are enabled on a cell board in the order 0, 3, 1, 2. This spreads the

CPUs across the two internal Cell Controller busses and allocates CPUs in

the best thermal fashion.

4. When a failed CPU is replaced, choose one from the same cell when possible.

If it is not possible, choose the next available CPU following rules 2 and 3.

Performance and High Availability For best performance, all cells in the

same partition should contain the same number of active processors. For

high-availability reasons, each cell should contain at least two active processors.

See also “Choosing Cells for Partitions” on page 325.