Delta value not calculating

[nmail_uk]

I'm trying to use Zabbix 1.6.4 on CentOS 5.3 to create a graph/statistics for the number of DNS queries processed per second so I can see when my servers are heavily used and for capacity management.

I've set up a command-line in the zabbix_agentd.conf of the DNS servers to get the number of DNS queries executed since the server was booted. If I set up a normal check in Zabbix, this value comes back fine (and confirmed with a telnet as follows):

root zabbix (networkmail): telnet zabbix_client_ip 10050
Trying zabbix_client_ip...
Connected to zabbix_client.
Escape character is '^]'.
bind.qcount
ZBXD123750Connection closed by foreign host.
root zabbix (networkmail):

(123,750 was the value at the time of the check.)

However I want to express this value as queries per second, and my understanding was that's what a delta would give me - it would store the change in value since the last check thus calculating the queries per second rate.

However if I change this check to a delta check, it records 0 as the result. Change it back and it records the number of queries.

Where am I going wrong?

Thanks,
Andy

[nmail_uk]

To answer my own question - I've changed the datatype of the item to "float" and it appears to be working correctly.