So, based on the following lines from the Redhat PDF on KVM:
....support for large memory systems with NUMA and integrated memory
controllers....
....NUMA support allows virtual machines to efficiently access large
amounts
of memory....
I decided to try out KVM as an alternative to the Xen setup we have been
using where guests are pinned to nodes and limited (by choice) to only
the available RAM at said node. This is a two socket, eight core, 72GB
system.
So I installed CentOS 5.4 and proceeded to use virsh-install to create a
guest, simply a CentOS 5.4 guest. I allocated it 40GB or so of RAM to be
sure memory allocation would cross node boundaries. I tried using
"vcpus=8", "cpuset=auto", "cpuset=1,2 vcpus=8" (that one caused all
sorts of problems and CPU lockups), "cpuset=1,2 vcpus=2", "cpuset=1,2"
No matter what I still see only one NUMA node in the guest from numastat
So what's going on here. Is the PDF misleading? Does a guest not need to
know about NUMA and all scheduling/NUMAness handled by KVM? Am I missing
some magical configuration line in the XML so the guest understands it's
NUMAness? When allocating memory to the guest does the virsh wrapper
make all the right backend calls to allocate exactly 50% of requested
memory from each physical socket's half of total system memory, in this
case 20GB from one socket and 20GB from the other?
Any useful comments appreciated.
Thanks!
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