Memory Sparing - IBM System x3850 X5 Implementation Manual

Table 4-15 DIMM population order: Memory-mirroring mode with the mezzanine installed
Sets of DIMMs
Set 1
Set 2
Set 3
Set 4
DIMM installation: MAX5
Table 4-16 shows the installation guide for MAX5 memory mirroring.
Table 4-16 MAX5 memory mirroring setup
4
8 x
12 x
16 x x x
20 x x x
24 x x x x
28 x x x x
32 x x x x x x

4.8.7 Memory sparing

Sparing provides a degree of redundancy in the memory subsystem, but not to the extent that
mirroring does. For more information regarding memory sparing, see "Memory sparing" on
page 29. This section contains guidelines for installing memory for use with sparing. The two
sparing options are DIMM sparing and rank sparing:
DIMM sparing
Two unused DIMMs are spared per memory card. These DIMMs must have the same rank
and capacity as the largest DIMMs that we are sparing. The size of the two unused DIMMs
for sparing is subtracted from the usable capacity presented to the operating system.
DIMM sparing is applied on all memory cards in the system.
Rank sparing
Two ranks per memory card are configured as spares. The ranks have to be as large as
the rank relative to the highest capacity DIMM that we are sparing. The size of the two
unused ranks for sparing is subtracted from the usable capacity presented to the operating
system. Rank sparing is applied on all memory cards in the system.
Number of installed
processors
2
2
2
2
x
x x
x x x x
x x x x
x x x x x
x x x x x x
x x x x x x x x
x x x x x x x x
DIMM connector
population sequence
on the system board
1, 8, 9, 16
3, 6, 11, 14
2, 7, 10, 15
4, 5, 12, 13
MAX5
x
x x x
x x x
x x x x
x x x x x
x x x x x x x
x x x x x x x
x x x x x x x x
Chapter 4. IBM System x3690 X5
DIMM connector
population sequence
on the memory tray
17, 24, 25, 32
19, 22, 27, 30
18, 23, 26, 31
20, 21, 28, 29
x x
x x
x x x
x x x x
x x x x x x
x x x x x x
x x x x x x x
x x x x x x x x
x
x
x
x
x x
x x
143