Select the host profile and click on Edit host profile.
Expand Advanced Configuration Settings and navigate to System Image Cache Configuration as shown here:
Select on Enable stateless caching on the host or Enable stateless caching to a USB disk on the host.
Provide inputs for Arguments for first disk or leave at default: this is the order of preference of disk on which the host would be used for caching. By default, it will detect and overwrite an existing ESXi installation, if the user indicates the specific disk make, model or driver used, the specific disk matching the preference is chosen for caching:
For the option Check to overwrite any VMFS volumes on the selected disk, leave it unchecked. This would ensure that if there were any VMs on the local VMFS volume, they are retained.
For the option Check to ignore any SSD devices connected to the host, leave it unchecked. You may need to enable this setting only if you have SSD for specific use cases for the local SSD, such as using vFlash Read Cache (vFRC).
