Command Line Interface Guide

130 omconfig: Managing Components Using the Instrumentation Service
Redundant memory enables a system to switch to other available memory
modules if unacceptable errors are detected in the modules that the system is
currently using. The omconfig chassis memorymode or omconfig
mainsystem memorymode command allows you to disable redundancy;
when you disable redundancy, you instruct the system not to switch to other
available memory modules when the module the system is using begins to
encounter errors. To enable redundancy, choose among spare, mirror, RAID, and
DDDC.
Spare mode disables a bank of system memory in which a correctable memory
event is detected, enables the spare bank, and copies all the data from the
original bank to the spare bank. Spare bank requires at least three banks of
identical memory; the operating system does not recognize the spare bank.
Mirror mode switches to a redundant copy of memory when an uncorrectable
memory event is detected. After switching to the mirrored memory, the
system does not switch back to the original system memory until the next
reboot. The operating system does not recognize half of the installed system
memory in this mode.
RAID mode provides an extra level of memory checking and error recovery at
the expense of some memory capacity.
The DDDC mode enables double device data correction. This ensures data
availability after hard failure of x4 DRAM.
NOTE: This command is applicable only on systems prior to PowerEdge yx2x
systems. To configure the attribute on PowerEdge yx2x systems, refer Table 4-4.