Centos – Unexpected RCODE(SERVFAIL) causing bind to crash

You can turn up debugging to see if that doesn't directly answer your question. However, I'd suspect that the permissions on your zone file aren't allowing the bind user to read the file.

I define all my logging options in named.logging.conf and then use an include in the main file:

logging {
        channel default_syslog {
                // Send most of the named messages to syslog.
                syslog local2;
                severity debug; 
        };

        channel audit_log {
                // Send the security related messages to a separate file.
                file "/var/named/system/named.log";
                severity debug;
                print-time yes; 
        };

        channel null {
                null;
        };

        category default { default_syslog; };
        category general { default_syslog; };
        category security { audit_log; default_syslog; };
        category config { default_syslog; };
        category resolver { audit_log; };
        category xfer-in { audit_log; };
        category xfer-out { audit_log; };
        category notify { audit_log; };
        category client { audit_log; };
        category network { audit_log; };
        category update { audit_log; };
        category queries { audit_log; };
        category lame-servers { null; }; 

};

and then in named.conf:

root@dnsm02:/etc/bind# grep logging named.conf
include "/etc/bind/named.logging.conf";

Additionally, you don't mention views, but if you have any views defined, then all of your zones must be in defined views.

You use named-checkzone.

$ named-checkzone tenebris.cs cs.db 
dns_rdata_fromtext: cs.db:13: near 'hermes.tenebris.cs.': not a valid number
dns_master_load: cs.db:22: www.tenebris.cs: CNAME and other data
zone tenebris.cs/IN: loading from master file cs.db failed: not a valid number
zone tenebris.cs/IN: not loaded due to errors.

The first error tells you that you have a problem with your MX record pointing to hermes.tenebris.cs. MX records take the format:

name           ttl  class   rr  pref name

You are missing the pref. Since you have only one, you can set this to any valid number between 0 and 65535. I tried 10.

The next error is with your CNAME. A CNAME cannot coexist with another record. You have a duplicate with www pointing to both an A record as well as a CNAME.

Remove the A record and now your zone should work!