Tag Archives: dump collector

No vmkcore disk partition is available

Sometimes I really do feel the computer gremlins are out to get me.  As long as I can remember I’ve had a flawlessly running Test Lab at work.  The day of my scheduled ESXi host upgrades I come across numerous hosts with the below error.

No vmkcore disk partition is available and no network coredump server has been configured.  Host core dumps cannot be saved.


I tried to ignore the error but VMware Update Manager would have no bar of it and prevented me from performing an ESXi version upgrade.

The error is referring to the location ESXi will dump its core during a Purple Screen of Death (PSOD).  Usually you’ll see this warning with a statless configured ESXi host.  In this situation a host will be running in memory with no disk.  You will usually configure the vSphere Network Dump Collector service.  This wasn’t the case in my situation.

Logging into the Shell I ran the follow

~ # esxcli system coredump partition list

no configured dump partition found; skipping

Next I attempted to set the coredump

~ # esxcli system coredump partition set --enable true --smart

Unable to smart activate a dump partition.  Error was: Not a known device: naa.6000097000024659483748380304235.

Not really sure what was going on here.  I just hope no one was messing with LUN mappings.

So next I use the set -u to unconfigure any current core dump follow by set --enable true --smart which allows ESXi to automatically determine the best location to set.

~ # esxcli system coredump partition set -u

~ # esxcli system coredump partition set --enable true --smart

~ # esxcli system coredump partition get

Active: naa.600601600fc04857394578c4d945e311:7

Configured: naa.600601600fc04857394578c4d945e311:7

This resolved the error immediately without any reboots and allowed me to continue with ESXi host upgrades.

I don’t know the root cause to this issue but as I’m upgrading ESXi versions I think it’s okay to sometimes let things go.

Note;  --enable true --smart contains double dashes.

Configuring ESXi 5 Dump Collector

I finally got around to setting up VMware’s Dump Collector.  It was so ridiculously simple I don’t know why I didn’t do it before.   I guess, let’s be honest, you’ll probably never need it.  ESX nowadays is pretty stable and if something does go wrong it’s usually just easier to wipe and refresh then to troubleshoot.

The the less I decided to set it up.  The benefit of setting up a dump collector would primarily be for support.  If you ever face a Purple Screen of Death (PSOD) and log a support call.  You’ll probalby be asked for a core dump.  This would usually be held on the local partition of the host.  If you use the Dump Collect to can actually direct this output to a network location for easy access.

Below are the steps I took to set this up.

1. Install the Dump Collector

Before configuring the ESX hosts you need to actually install the Collector that will act as the repository for any system dumps from ESX.  This can be found on the VMware vSphere 5.0 Installation image.  I chose to install this on our vCenter Server but you can install it anywhere.

2. Choose Language.

3. Start Wizard

4. Accept Agreement

5. Accept License

6. Chose where to install to program data and where to store the repository.

I chose to keep all default settings.

7. Setup Type

I chose to Integrate with my vCenter and selected the second option.

8.vCenter Information

Enter the address of your vCenter server.  Leave the default port unless you changed it during your vCenter installation.  The username you use here will be the account that will run the service.  You can use a local account on the server or if running AD probably recommended to create a standard AD account and run it off this.

9. Port Settings

6500 is the default port and is fine to accept and click next.

10. Select an Interface on the Dump Collect to use.

11. Install

12. Finish

That’s it!  Simple.  Now we go and configure our ESX hosts to send to this collector.

Configuring the ESX Host

Configuring the hosts are pretty easy too.  You can go to the local host but I found that too much trouble to get a terminal screen, enable the shell, run the commands, and turn off the shell.  Instead go get the vCLI (if you don’t already have it) and do it from your desktop.

It’s two simple commands.

The first command configures the host to send its dumps to the collect using the vmkernel interface 0

esxcli –s ESXHOSTNAME system coredump network set –interface-name vmk0 –server-ipv4 –server-port 6500

This second command then enables the setting just made.

esxcli –s ESXHOSTNAME system coredump network set –enable true

This last command verifies what you have just set.

esxcli –s ESXHOSTNAME system coredump network get

During each of the commands you’ll be asked for a username and password.  Enter in a privileged account on the ESX host.

..and you’re done.

There is one note worth mentioning.  Dump Collector only works on Standard Switches.  If you run only Distributed Switches it will not work on those hosts.  There are alternative methods for System Dumps on these Hosts which I’ll detail at a later stage.