[3] As the number of domains and internet hosts skyrocketed, so too did the quantity of DNS data and the time required to manage it.
Sysadmins responded by writing Perl or Shell scripts that helped automate DNS changes.
DNS changes were made by telnetting to a BIND master and editing zone files with a text editor.
While struggling with the challenges of editing zone files, more than a few sysadmins noticed that SQL is a terrific place to store DNS data.
By moving the Single Source of Truth from text files into SQL, DNS data could be validated and constrained before acceptance into the database.
Among large hosting providers, it became fashionable to store DNS data in SQL and build a custom interface for managing it.
One of its features was the ability to serve DNS data directly out of the SQL database, bypassing the export step entirely.
PowerDNS also spawned a number of DNS managers that provide web interfaces to its SQL data store.
Code diversity makes it less likely that a performance or security bug in one DNS server could be exploited to inflict a Denial of Service attack upon an organization.