VMware ESXi Scratch Space

If you installed VMware ESXi on a USB stick like I did, the “scratch space” (used for storing logs and debug information) is stored on a RAM disk.  This takes up 512MB of memory that could otherwise be provisioned to virtual machines.  In addition, it does not persist across reboots, which explains why I was never able to find any logs after a crash. Also I was seeing random “No space left on device” errors when I was trying to run the munin monitoring script for ESXi.

The solution to this is to simply create a folder on a disk, and configure ESXi to use it.

  1. Login to the console or SSH to the host.
  2. Go into one of your datastores in /vmfs/volumes/
  3. Create a directory for the scratch space.
  4. Login to the vSphere Client.
  5. In the Host device, go to the Configuration tab, then find the Software category on the left menu and click Advanced Settings
  6. In the Configuration parameters window, find ScratchConfig on the left.
  7. For the “ScratchConfig.ConfiguredScratchLocation” box, enter the path to the folder you created in step 3.
    ESXi Advanced Settings Window
  8. Reboot the host.

It’s as simple as that!

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