Memory - IBM eServer xSeries 440 Quick Reference

Memory

What is Memory Mirroring?
Memory mirroring is an Active Memory
and availability. This feature provides protection for memory that is analogous to what
RAID-1 disk mirroring provides for hard disk drives.
With the same amount of memory in both memory ports and memory mirroring
enabled in the BIOS code, the data from the first memory port is copied or mirrored in
the second memory port, giving you a 100% redundant copy of the data stored in
memory. In addition, if one memory port is disabled or fails, the data stored in memory
remains accessible through the redundant copy in the remaining functional memory
port.
What should be done if the system reboots and reports only half of the
memory installed?
1. Verify that:
2. Look in the POST error log for error message 289:
3. If a second SMP Expansion Module is installed, check to see if it has been
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Hints, Tips, and Frequently Asked Questions for the xSeries 440:Quick Reference
• The memory modules are seated properly.
• You have installed the correct type of memory.
• If you changed the memory, you used the Configuration/Setup Utility program
to update the memory-configuration information.
• All banks of memory on the DIMMs are enabled. The server might have
automatically disabled a DIMM bank when it detected a problem, or someone
might have disabled a DIMM bank manually.
• If a DIMM was disabled by a system-management interrupt (SMI), replace the
DIMM.
• If the DIMM was disabled by the user or by POST:
a. Start the Configuration/Setup Utility program.
b. Enable the DIMM.
c. Save the configuration and restart the server.
disabled. (See "Installing an SMP Expansion Module" on page 15 for more
information.)
™
feature that offers greater memory reliability