NetScaler ECV monitors not only check if the server is up, but also check if the requested content is present on the website. If you are requesting “200” as a response in ECV monitor, then the “200” must be present in HTML body on the website. HTML is returned in HTTP message body.
HTTP and HTTPS monitors check if the web server is up and running, and it returns HTTP message 200 OK.
HTTP-ECV and HTTPS-ECV monitors check if web server is up by checking the requested content is present on the web server.
HTTP-ECV Monitors will search for the text string defined in the parameters.
For example, a monitor might be defined to probe a web server that is a front end to a database, and the HTTP response should be checked to ensure that the web server is querying the database correctly.
The HTTP-ECV monitor uses the following parameters:
send [“”] – HTTP data is sent to the service
recv [“”] – the expected HTTP response data from the service
As an example, you can define a custom HTTP-ECV monitor as follows:
> add monitor <name> http-ecv –send “GET /siteup.html” –recv “site_is_up”
This monitor causes a NetScaler appliance to probe the back end HTTP service that is bound to a monitor with a HTTP GET request for the file %wwwroot%/siteup.html. The appliance expects to receive a response containing the string “site_is_up”.