Master and slave servers

[mike@snix]

I have two DNS servers running on RedHat 6.1.  I have one acting as the
primary and one as the secondary.  I have the secondary pointing to the
primary as a slave.  If the primary goes down, will the slave serve the DNS?
Or do I need to have the files located on the secondary and set ip up as a
master as well?

Thanks for any help.