A quick note about an error I faced while running root.sh on an Exadata machine. The configuration tools failed with the following error:

Error is PRVF-4657 : Name resolution setup check for "db-scan" (IP address: x.x.x.101) failed

I did nslookup on the scan name and it all seemed good. So why the error ? After spending another 5 minutes, I looked at /etc/hosts and there was it. Someone had populated /etc/hosts of DB nodes with all the hostnames entries including the scan name. Something like:

x.x.x.101	db-scan.example.com	db-scan
x.x.x.102	db-scan.example.com	db-scan
x.x.x.103	db-scan.example.com	db-scan

As /etc/hosts can return only one IP against a hostname whereas for scan, DNS is supposed to return 3 IPs, hence the problem. The solution is to comment out the scan name entries in /etc/hosts on all the db nodes and let the system do the name resolution via the DNS.