Host and guest system freeze after several hours

[b.s.]

Hello,

I have installed RHEL6.3 on the host system and on the guest systems. I also have installed the Guest Additions.

I use VirtualBox 4.3.6.

I have the following different guest configurations:

Machine 1:

(8 GB RAM, 500 GB Hard Disk, 8 CPU)

guest1: Client with GUI (gnome)

(2 GB RAM, 50 GB Hard Disk, 2 CPU, Port 5000)

guest2: Server (without GUI), headless

(4 GB RAM, 50 GB Hard Disk, 4 CPU, Port 5100)

Machine 2:

(8 GB RAM, 500 GB Hard Disk, 8 CPU)

guest1: Client with GUI (gnome)

(2 GB RAM, 50 GB Hard Disk, 2 CPU, Port 5000)

guest2: Client with GUI (gnome) headless

(2 GB RAM, 50 GB Hard Disk, 2 CPU, Port 5100)

Machine 1 works without problems when the 2 guest machines are running.

Machine 2 works without problems, when only guest1 runs. When I start guest2 after several hours all the guests and the host system freeze, so I have to do a hard reset (power off/on).

[b.s.]

On the host machine are 2 monitors connected. The guest1 machines are also running in headless mode. After the VM's are started up, I start the X-Server on the host machine and then I connect via rdesktop to the guest1, to use the 2 monitors.

After the reboot I can't see anything in the logs (host and guest systems)

On the host system I have installed an NVIDIA Quadro 410 graphics card with the latest driver (331.60) from nvidia.

3D Acceleration is in the guest machines is not enabled.

[Frank Mehnert]

Please attach VBox.log files of VM sessions of VM1 and VM2 when running in parallel.

[b.s.]

Yesterday I have downgraded to Virtualbox 4.2.16 and the two machines are still running parallel.

[Frank Mehnert]

I see that both VMs are set up to use the host DVD drive /dev/sr0. Any difference if you don't use the same device by both VMs? Also does it make any difference if you decrease the number of virtual CPUs for both VMs to 1?