VirtualBox is capable of producing its own core files for extensive debugging when things go wrong. Currently this is only available on Solaris hosts.
The VirtualBox CoreDumper can be enabled using the following command:
VBoxManage setextradata "VM name" VBoxInternal2/CoreDumpEnabled 1
You can specify which directory to use for core dumps with this command:
VBoxManage setextradata "VM name" VBoxInternal2/CoreDumpDir <path-to-directory>
Make sure the directory you specify is on a volume with sufficient free space and that the VirtualBox process has sufficient permissions to write files to this directory. If you skip this command and don't specify any core dump directory, the current directory of the VirtualBox executable will be used (which would most likely fail when writing cores as they are protected with root permissions). It is recommended you explicitly set a core dump directory.
You must specify when the VirtualBox CoreDumper should be triggered. This is done using the following commands:
VBoxManage setextradata "VM name" VBoxInternal2/CoreDumpReplaceSystemDump 1 VBoxManage setextradata "VM name" VBoxInternal2/CoreDumpLive 1
At least one of the above two commands will have to be provided if you have enabled the VirtualBox CoreDumper.
Setting CoreDumpReplaceSystemDump
sets up the VM to override the host's core dumping mechanism and in the
event of any crash only the VirtualBox CoreDumper would produce the core
file.
Setting CoreDumpLive sets up the VM
to produce cores whenever the VM process receives a
SIGUSR2 signal. After producing the core
file, the VM will not be terminated and will continue to run. You can thus
take cores of the VM process using:
kill -s SIGUSR2 <VM-process-id>
Core files produced by the VirtualBox CoreDumper are of the form
core.vb.<ProcessName>.<ProcessID>,
for example core.vb.VBoxHeadless.11321.