Secondary DNS servers

I am running a backup server hosted outside a data center. This server is meant to work as an ancillary services provider and as a backup mail server.
I assigned it a domain, installed it as an Ubuntu Lucid LTS machine with a bind DNS server, and needed a backup server.
After some research, I decided to try Buddyns. I can tell that it completely meets my expectations. It was extremely easy to setup according to their setup page, and after a frustrated trial with a cpanel-managed site I found out there was people behind the box...Support exists and is great.

To have an idea of your dns speed you may use the simple linux script:

#!/bin/bash

# calculate dns server speed

if [ $# -eq 0 ] # Must have command-line args to script.
then
echo "Usage ./dnspeed "
exit $E_NO_ARGS
fi

n=10
t=0.0

for (( i=1; i<=$n; i++ ))
do
start=$(date +%s.%N)
host $1
end=$(date +%s.%N)
e=$(echo "$end - $start" | bc)
#echo DNS query took $e seconds
t=$(echo " $t+1000*$e" | bc)
done
t=$(echo "scale=0; $t/$n" | bc)
echo DNS query took an average of $t milliseconds

or use something like this:

let's look at our main, data-center located dns server acutron.net and acutron.eu, where we have used Buddyns. Of course this is simplistic (does not take the location into account), but gives you a raw idea:

acutron.net using its datacenter server
Average response time of DNS Server 109.71.43.83 is: 0.1655s

acutron.eu using its own server
Average response time of DNS Server 87.103.12.6 is: 0.1713s

acutron.eu using buddyns
Average response time of DNS Server 173.244.206.26 is: 0.0512s

To end up, reliability is great, no down-time has ever been detected.

I am not affiliated in any way with Buddyns. As it is a free service and it works reliably and is properly supported I just recommend it.