I'm using VirtualBox on a Windows Server 2008 R2 host system with 24GB RAM. I want to allocate 12GB of RAM to my 64-bit CentOS guest, but when I change the RAM slider to more than 8GB the VM will only see 8GB of RAM:
Reserving 129MB of memory at 48MB for crashkernel (System RAM: 8704MB)
# free -m total used free shared buffers cached Mem: 7870 5025 2845 0 13 90 -/+ buffers/cache: 4921 2949 Swap: 4099 0 4099
Is there a limitation on how much RAM a guest can have? I didn't find anything on the net.