It's an strange behaviour as the ESXi host doesn't have a swap file.
Anyway, could you check if you have enough space in the ESXi's local datastore?
Also, I would check the .vxpd log in order to see what it's bothering DRS even is disabled.
If there are no hints, I would suggest to Remove the host from the cluster and then adding it again.
That error can be safely ignored. To clear it, restart the ESXi management agents:
SSH into the ESXi host and type: services.sh restart
Put the host in maintenance mode and, you guessed it, restart the management services. Once the ESX host reconnected, the error and the red exclamation disappeared. This is yet another case where there was a disconnect between the ESX hosts and vCenter Server instance.
Please consider marking this answer as correct and helpful if this helps you.
check scratch partion.
Remove the scratch partion path and reboot the host.
This post is a little old, but for the sake of anyone else running across this post, I thought I'd share what fixed this for me.
I recently had this same issue:
DRS resource settings could not be successfully applied to a host in the cluster....
I found the time setting on this host was out of sync with other hosts in the same cluster. For some reason, the host showing the error message was about 5 hours ahead of the other hosts in the cluster.
I manually set the time to match the other hosts, refreshed vSphere Web Client and the Error message cleared immediately.. I will go back in to confirm NTP is working.
This could be a different issue for you, but it's worth a look.