The memory configuration of each
cell should include a multiple of two memory ranks (first-generation cell-based
HP 9000 servers) or a multiple of two memory echelons (servers based on the
HP sx1000 chipset or HP sx2000 chipset) per cell.
the first generation of cell-based HP 9000 servers, each memory rank is 4
DIMMs. If possible, install memory in sets of 8 DIMMs: 8 DIMMs or 16 DIMMs
on HP rp7405/rp7410, rp8400, and Superdome (SD16000, SD32000, SD64000) cells.
On Superdome cells, you also can install 24 DIMMs or 32 DIMMs per cell.
On servers based on the HP sx1000 chipset or HP sx2000
chipset, each memory echelon is 2 DIMMs. If possible, install memory in sets
of 4 DIMMs: 4, 8, 12, or 16 DIMMs. On Superdome servers, you also can install
20, 24, 28, or 32 DIMMs per cell.
This provides a performance improvement by doubling the
memory bandwidth of the cell, as compared to having one memory rank or memory
This also can provide an availability improvement, in that
if one memory rank or echelon fails the cell still has at least one functional
rank of memory.
(Memory rank 0, or echelon 0, must be functional for a
cell to boot.)