After applying vSphere 6.0 Update 1, Veeam backup job fails with an "NFC storage unavailable" error due to the protocol SSLv3 disabled by VMware for security reasons.
Since Veeam Backup & Replication is designed to use TSL or SSL, due to a bug in the parsing the list of supported SSL/TLS protocol versions, Veeam backup job fails because doesn't use TLS for NFC communications if SSL fails.
Fastest but less secure workaround is to enable the support for SSLv3 on Authd service 902 in ESXi again.
Connect the host ESXi to edit using an SSH client like PuTTY.
Make a backup of /etc/vmware/config file.
# cp /etc/vmware/config /etc/vmware/config.bak
Edit the /etc/vmware/config file and append the following line at the end of the file:
vmauthd.ssl.noSSLv3 = false
# vi /etc/vmware/config
Restart the rhttpproxy service with the command:
# /etc/init.d/rhttpproxy restart
Repeat same procedure for all other hosts in the cluster.
Run the failed Veeam backup job again.
This time the backup job has been completed successfully.
Veeam has a hotfix to solve this matter that will be included in the upcoming Veeam Backup & Replication 8.0 Update 3.