Updating Zone file (serial # increment)...

okay,

i have successfully setup primary and secondary dns servers.
when i restart both of them, my changes are picked up.

When i add a new zone file for a new domain, do i have to increment that serial number? even if it's a brand new file?

I want to update and add new zone files on a regular basis without having to restart the servers.

Actually, very rarely will i ever update an existing zone file, mostly i'll just be creating new ones. Do i still have to increment serial number on a new zone file?

The serial number is to be used for master to sync the zone records to its slave. That said, on a brand new zone file (assuming the named.conf on master and slave and the zone files on master are configured properly) you need not to increment its serial at all.

>> without having to restart the servers

You can use the ndc utility or give named a HUP signal.