interval_length, normal_check_interval and real interval bet

max_check_attempts 2
normal_check_interval 2
retry_check_interval 1

interval_length=60

But in nagios.log i see:

[1207490884] SERVICE ALERT: host;LOAD;OK;SOFT;2;LOAD ok - all ok
[1207491044] SERVICE ALERT: host;LOAD;WARNING;SOFT;1;LOAD WARNING - [WR LoadAverage 28.85]
[1207491164] SERVICE ALERT: host;LOAD;CRITICAL;HARD;2;LOAD CRITICAL - [ER LoadAverage 35.69]
[1207491334] SERVICE ALERT: host;LOAD;WARNING;HARD;2;LOAD WARNING - [WR LoadAverage 13.95]
[1207491824] SERVICE ALERT: host;LOAD;OK;HARD;2;LOAD ok - all ok

Time:
6:08:04 p.m.
6:10:44 p.m. (2:40 min)
6:12:44 p.m. (2 min)
6:15:34 p.m. (2:50 min)
6:23:44 p.m. (8:10 min)

Why ???

How many host and service checks do you have? Maybe your Nagios server is in some kind of an overload and it doesn’t get to do all the check in a defined time manner. Such situation I have at my location.