While upgrading ESXI hosts from 6.0 U1 to 6.0 U3 , i got this warning as showing in below image
The impact of this warning is ,host keeps it’s logs as a temporary files and will be deleted after a reboot, these logs might need for further troubleshooting ,identify issues and auditing tasks of your environment.
to solve this issue you need to specify a storage directory to keep these log files
from vSphere web Client navigate to host then chose manage > settings > System > Advanced System settings
Specify a Datastore which can store these log files with a folder , but the Datasotre Name between the square brackets [<datastore_name>]/scratch/log” as the parameter and click “OK”.