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This blog is intended to provide information on debug issues encountered in Microsoft Support, such as STOP errors or hanging servers.

INFO: Capturing dumps of hung/frozen vms

INFO: Capturing dumps of hung/frozen vms

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Hi All,


In Support we frequently use memory dumps as a tool to troubleshoot problems, such as a hung or frozen machine. Sometimes however, capturing a dump proves anything but trivial, and it may take extended amounts of time and effort to finally get the data we want. Now, when working with virtual machines, I still see engineers struggle with capturing a memory dump of a hung vm. However, both Hyper-V and VMware provide functionality to capture the machine state and convert the state file(s) - vsv/bin on Hyper-V, vmss on VMware -, to a dump file that can be read into WinDbg. Converting is simple: on Hyper-V use vm2dmp, on VMware use vmss2core (thanks to Paudie from VMware for sharing this link with me).

Let me know if this bit of info helped you!

Note: should you want to go the "old" way of getting dumps on vms, then you'll surely appreciate the virtual NMI functionality in Hyper-V 2012 R2. ;)


  • Thanks for the mention Rob.

    also from VMware side take a look @ KB

    This shows you the ins and outs of collecting a .vmss file (which is essentially a file generated on the Virtual Machines home directory when you suspend a Virtual Machine on ESX for example

  • How about use livekd?

    livekd -o memory.dmp -p -hv VMNAME

  • Indeed, livekd is another option. :)

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