The NetScaler provides the ability to ensure the response from an application in spite of server capacity or processing speed, called SureConnect. SureConnect eliminates the gap between the client expectations and their browsing experience and improves the real and perceived availability of a Web site.
You can use the SureConnect feature of the Citrix® NetScaler® appliance to service all incoming connections with either the requested content or a custom Web page that displays information about a delay in the request being serviced.
When servers are overloaded with the requests, the servers might either respond slowly or not at all. The SureConnect feature enables the NetScaler appliance to detect and compensate such conditions by ensuring that every client request gets serviced in some way, such as either a custom Web page or actual content is sent to the client.
SureConnect is activated when the response time or maximum server connections to a client request exceeds a limit that you have set. The SureConnect browser window displays one of the following:
- A progress bar with the amount of time remaining until the requested content will be available.
- Alternate Web content of your choice (alternate page).
- Both a progress bar and alternate page.
- Complete custom content of your choice.
When the load balanced servers become responsive again, the original request for content is served.
SureConnect is advantageous in the following situations:
- Full server queue: The server can respond fast, but there are too many users. This results in the server’s queue being full and unable to process additional client requests. In this situation, the SureConnect window is displayed, showing the time left until the content will be available. The alternate page is displayed under the progress bar, if an alternate page has been configured.
- Large response delay: The server response is slow. If a Web server does not respond to a client request quickly, the user will leave the site. When the predicted delay reaches a configured time threshold, the SureConnect window displays the progress bar and the optional alternate page in the client browser.
- Client time-out: When the client requests content from a very slow Web site, a time-out message displays in the client browser, and the content is not delivered. The user may leave the site. The appliance stores the request until the server is no longer busy and delivers the requested content to the client.
- Server experiencing a traffic surge: The server typically responds quickly, but the current load of open connections is greater than the server capacity to serve them. Therefore, the server response is delayed. A SureConnect window is displayed in the client browser, showing the time left. The alternate page from the server is also displayed if it has been configured.
To set SureConnect on a virtual server by using the NetScaler command line
set lb vserver <vServerName> -sc <Value>
To set SureConnect on a virtual server by using the configuration utility
- In the navigation pane, expand Load Balancing, and then click Virtual Servers.
- In the details pane appears, select the virtual server for which you want to configure SureConnect (for example, Vserver-LB-1), and then click Open.
- In the Configure Virtual Server (Load Balancing) dialog box, click the Advanced tab.
- Select the SC check box, and then click OK.