VM crash if CPU Socket is > 1 Filesystem corrupted

Hello,

I've tried to add more Sockets and Cores to an VM with Debian 7.2 insde.
The Configuration with 1 Socket and 4 cores, the system runs stable for over 6 months.
Now I've tried to change the Configuration to 2 Sokets and each with 4 Cores.
A week after this Change, the VM hangs, crashes and the root filesystem get corrupted.
I've no idea what is the problem. Bug?
Any ideas?

Server is a HP DL380 G7 2x Xeon E5645 with HT -> 24 Thread and 64 GB Ram

thanks for help,
s.gruner

pveversion -v:
running kernel: 2.6.32-22-pve
proxmox-ve-2.6.32: 3.0-107
pve-kernel-2.6.32-22-pve: 2.6.32-107
pve-kernel-2.6.32-20-pve: 2.6.32-100
pve-kernel-2.6.32-16-pve: 2.6.32-82
pve-kernel-2.6.32-19-pve: 2.6.32-93
lvm2: 2.02.95-pve3
clvm: 2.02.95-pve3
corosync-pve: 1.4.5-1
openais-pve: 1.1.4-3
libqb0: 0.11.1-2
redhat-cluster-pve: 3.2.0-2
resource-agents-pve: 3.9.2-4
fence-agents-pve: 4.0.0-1
pve-cluster: 3.0-4
qemu-server: 3.0-20
pve-firmware: 1.0-23
libpve-common-perl: 3.0-4
libpve-access-control: 3.0-4
libpve-storage-perl: 3.0-8
vncterm: 1.1-4
vzctl: 4.0-1pve3
vzprocps: 2.0.11-2
vzquota: 3.1-2
pve-qemu-kvm: 1.4-13
ksm-control-daemon: 1.1-1