[Pdns-users] Questions about PowerDNS - CNAME at APEX, Capacity, management, etc...

[Jan-Piet Mens]

>Does PowerDNS load all of the zones into memory, and then start 
>serving (like BIND), or does it load each zone and start serving said 
>zone immediately upon load (like KNOT)?

Neither nor. It waits for a query and then goes to the backend to search
for an answer to that query, unless the answer is already in the 
packet cache in which case it answers from there.

>What's the best method for updating a backend with DNS changes in an 
>instance where there are 6 million+ zones?

'best' is relative. You might want to use SQL if you have an appropriate
bakend, RFC2136 dynamic updates, or the API. I would conduct tests
to determine what's 'best' for you.

>                              Is my assumption correct that I only 
>have to worry about this in a "primary" configuration, and that a 
>"secondary" configuration can rely entirely on standard zone 
>transfers?

Correct.

>CNAME @ APEX questions:

There is no such thing. "No CNAME and other data" is the rule.

>Can a PowerDNS instance handle 6 million zones and 300 million records?

Probably. It's likely a backend issue and a volume of queries issue.

>What is the startup timing on a large PowerDNS installation?
>example:  "I have $x million records, and that takes $y minutes until 
>loaded?

PowerDNS launches equally fast with 0 and with millions of records.

	-JP