Scalability, data locality and decentralisation
The allow the high availability of all the cluster, it's important always return a dns entry, include stale.
The stale entry remain in general valid. And prevent shutdown in case of forwarder problem.
- If not in cache, get and store into cache
- If in cache:
- If fresh entry: return it
- If not fresh entry (stale entry), try get a new version:
- If success: store into cache and return it
- If failed return stale cache entry
For ISP mean the local web site continue to work, event if the global internet have failure (frequent case into Bolivia, Bolivia internet is frequently isolated of the rest of the work)