Users Guide

omconfig: Managing Components Using the Instrumentation Service 81
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, and RAID.
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.
Table 4-9 shows the valid parameters for the command.
Table 4-9. omconfig chassis memorymode/omconfig mainsystem memorymode
name=value pair 1 Description
index=<n> Number of the chassis where the memory module resides (the default is
chassis 0, the main system chassis).
redundancy=spare |
mirror | disabled |
raid5
Spare disables the memory module that has a correctable memory event
and copies the failing module’s data to a spare bank.
Disabled indicates that the system is not to use other available memory
modules if uncorrectable memory events are detected.
Mirror switches the systems to a mirrored copy of the memory if the
failing module has an uncorrectable memory event. In the mirror mode,
the operating system does not switch back to the original module until
the system reboots.
RAID-5 is a method of system memory configuration. This is logically
similar to the RAID-5 mode used in hard drive storage systems. This
memory mode provides an extra level of memory checking and error
recovery at the expense of some memory capacity. The RAID mode
supported is RAID level 5 striping with rotational parity.