User`s guide

SGI
®
Altix
®
XE210 User’s Guide 31
Memory Sparing Mode
To select memory sparing mode, you must select sparing in the BIOS setup:
Advanced --> Memory --> Configure Memory RAS and Performance
Figure 22 illustrates the standard DIMM population for sparing mode.
Figure 22. Standard DIMM Population for Sparing or Mirroring Mode
Memory Mirroring Mode
The memory controller supports memory mirroring to prevent data loss in case of DIMM
failure. The system maintains two copies of all the data in memory; therefore, a mirrored
system uses only half of the installed DIMMs. If a DIMM fails, the system recovers the
second copy of data from the mirrored DIMM in the opposite channel. If both the primary
and the mirrored copy of the data becomes corrupt, the system will fail.
To select memory mirroring mode, you must select mirroring in the BIOS setup:
Advanced --> Memory --> Configure Memory RAS and Performance
Figure 22 illustrates the standard DIMM population for mirroring mode.
The minimum number of DIMM supported in mirror mode is four. All four DIMMs must
be identical in size, speed, and organization.
Mirroring Mode Upgrade
To upgrade DIMM memory in mirroring mode, you must add four additional DIMMs.
The additional four must be identical to initial four, except for speed. The MCH will
adjust to the lowest-speed DIMM.
yes
yes
DIMM A1 DIMM A2 DIMM B1 DIMM B2 DIMM C1 DIMM C2 DIMM D1 DIMM D2
Channel A
Branch 0
Channel B
Channel C
Branch 1
Channel D
yes
yes
Sparing
Possibl
e
Mirroring
Possible