A health check is performed on each Real Server. The retry interval defines the amount of time (in seconds) between checks. The following command sets the RetryInterval to 12 seconds: 

curl -k "https://bal:1fourall@20.200.25.100/access/modhealth?RetryInterval=12"

Response: 

<?xml version="1.0" encoding="ISO-8859-1"?>
<Response stat="200" code="ok">

<Success><Data><RetryInterval>12</RetryInterval>

<Timeout>4</Timeout>
<RetryCount>2</RetryCount>
</Data>
</Success>
</Response>