HP ProLiant DL980 G7 Maintenance And Service Manual page 41

To configure memory for Mirrored Memory mode, observe these additional constraints:
For the server to support Mirrored Memory, all processors must have a valid mirroring
configuration.
The minimum allowable configuration is two memory cartridges per processor.
Both memory cartridges for each processor must be populated with the same DIMM
configurations.
Both of the CPU sockets on the same QPI island must be loaded with identical memory.
NOTE: When attempting to install or boot VMware ESX 4.1 on a ProLiant DL980 G7 server
with Advanced Memory Protection (Memory Mirroring) enabled, the following error message
will be displayed:
The system has found a problem on your machine and cannot continue.The BIOS will report
that NUMA node 1 has no memory. When implementing memory mirroring on the ProLiant
DL980 G7 server, the sockets are paired so that the even socket of each pair is considered
primary and the odd socket is the mirror. However, the system reports that the cores on the
odd sockets do not have any local memory.If Memory Mirroring is enabled prior to VMware
installation, then immediately after BIOS POST and when the VMware installation begins,
press F2 and add the following line to the boot options:useNUMAInfo=falseAfter installation,
the system will reboot. Perform the following:
1. At the boot menu, press "a" to modify the kernel argument and add "useNUMAInfo=false"
to the end of the "grub append>" line.
2. Boot to VMware ESX 4.1.
3. Log into the newly installed VMWare Server with vSphere Client or vCenter Client.
4. Navigate to: Configuration Panel -> Software Advanced Settings -> VMKernel
5. Uncheck "VMkernel.Boot.useNUMAInfo" to disable NUMA.
If Memory Mirroring will be enabled after VMware is installed, perform the following:
6. Log into the installed VMWare Server using the vSphere Client or vCenter Client
application.
7. Navigate to Configuration Panel -> Software Advanced Settings -> VMKernel.
8. Uncheck "VMkernel.Boot.useNUMAInfo" to disable NUMA prior to enabling memory
mirroring.
NOTE: If all installed memory is configured for a single CPU on a ProLiant DL980 G7 server
running Red Hat Enterprise Linux 5, an error message similar to the following may appear
when the server is operating under a heavy workload, prior to the server becoming
unresponsive:
soft lockup - CPU#21 stuck for 10s!This occurs because configuring all server memory for a
single CPU results in contention of all other CPUs for communication to the single node
configured with memory. This contention is exacerbated when running processes with high
memory resource requirements.This issue is not specific to the HP ProLiant DL980 G7 server.
Any server using the Non-Uniform Memory Access (NUMA) multiprocessing architecture when
all memory is configured for a single CPU may be affected. Although this has been observed
under Red Hat Enterprise Linux 5, it may also occur under Red Hat Enterprise Linux 4 and
SUSE Linux Enterprise Server 10.Recent Linux kernels (for example, kernels in Red Hat Enterprise
Linux 6.x and SUSE Linux Enterprise Server 1 1) have improved methods for dealing with
memory and should not experience this issue. To avoid this issue when running Red Hat
Enterprise Linux 4, Red Hat Enterprise Linux 5, or SUSE Linux Enterprise Server 10, utilize the
DIMM installation guidelines
G7server:
("DIMM installation guidelines" (page 35)) for the ProLiant DL980
DIMMs 41