Imagine we come across a very critical Virtual Machine hosted on VMware platform which is hung at a particular stage. We see that either the machine has freezed at a screen or has been hung at Blue screen of death. What options do we have rather than hard rebooting the machine to bring back the primary functionality of the Virtual Machine online but we often being asked the question as to why the machine got to where it was and how can we avoid it from happening again.
Yes, we all know if we have configured Crash Dump or Minidump settings on the guest OS, we would definitely be able to analyze the dump to understand the state of the Virtual Machine at that stage. However if we do not have Crash Dump Collection Enabled on any machine or if you feel the Pagefile is not configured enough to capture a crash dump or if you realise that the space where the Dump has to be created is not sufficient then we would not get the desired Crash dump for analysis. Well in that case, before rebooting the server, we can take a Virtual Machine snapshot.
Yes, This snapshot can be converted into a Memory Dump which can be then analyzed using various debugger tools like Windebug etc.
1. Download the vmss2core.exe tool
2. Copy it to one of your Windows Server having sufficient free space
3. Copy the Snapshot File [.vmss] from the datastore, where the VM is located, to the same location where vmss2core.exe is residing
4. Run the utility to convert the snapshot to dump as shown below
vmss2core -W VM_Snapshot_Filename.vmss
5. This will convert the Snapshot File to Memory Dump that we can use to analyse the cause of Server Hung
0 comments: