[tor-relays] [warn] eventdns: All nameservers have failed

Jun 19 20:24:38.000 [warn] eventdns: All nameservers have failed Jun 19 20:24:38.000 [notice] eventdns: Nameserver 8.8.4.4:53 is back up

I do get this in my logs on an exit (Tor 0.2.7.6) several times every hour.

The /etc/resolv.conf contains

# Generated by SolusVM nameserver 8.8.8.8 nameserver 8.8.4.4

Is it really best to set only one DNS like specified here https://trac.torproject.org/projects/tor/ticket/11600 ?

Or are there better working solutions?