Limit informational messages from the virtual machine to the VMX file to avoid filling the datastore and causing a Denial of Service (DoS). A Denial of Service can occur when you do not control the size of a virtual machine's VMX file and the amount of information exceeds the datastore's capacity.

About this task

The configuration file containing the informational name-value pairs is limited to 1MB by default. This capacity is sufficient in most cases, but you can change this value if necessary. For example, you might increase the limit if large amounts of custom information are being stored in the configuration file.


Consider carefully how much information you require. If the amount of information exceeds the datastore's capacity, a Denial of Service might result.

The default limit of 1MB is applied even when the sizeLimit parameter is not listed in the VMX file.


  1. On the ESXi system that hosts the virtual machine, browse to the VMX file.

    Virtual machine configuration files are located in the /vmfs/volumes/datastore directory, where datastore is the name of the storage device on which the virtual machine files reside. For example, /vmfs/volumes/vol1/vm-finance/.

  2. Use a text editor to add or edit the following line in the VMX file:
  3. Save and close the file.