.vmss file and memory dump

The *.vmss file is used the store the entire system state with memory content when a virtual machine is put suspended and the file will be used to resume the virtual machine to the same state later.

1. The suspend and resume feature for a VM guest is especially useful when you have to put the VM off and restart the Host when maintenance, it could reduce interrupt of the VM guest
2. If the file is delete after the the VM has been suspended , the VM will start as normal boot or cold boot
3. The file will be reused when next time the VM goes suspend 
4. The file size is nearly same with the RAM size 

The .vmss file can be converted to memory.dump by Vmware vmss2core.exe tool, the brief step here:http://support.citrix.com/article/CTX125086 and the memory.dump file can used as further troubleshooting.

Ref:
http://pubs.vmware.com/vsp40_e/wwhelp/wwhimpl/js/html/wwhelp.htm#context=admin&file=t_suspend_a_virtual_machine.html

http://www.vmware.com/pdf/snapshot2core_technote.pdf