Product Documentation

Troubleshooting

Nov 23, 2015
The statistics from the NetScaler VPX appliance indicate that the appliance has reached the session persistence limit. As a result, persistence sessions are failing. Is possible to increase the session persistence limit?

Cause: The NetScaler appliance has the system limit of 250,000 persistence session for a core.

Resolution: To resolve this issue, you can perform any of the following tasks:
  • Reduce the time out value for persistence
  • Increase the number of cores for the appliance
After configuring Cookie Insert persistence on the NetScaler appliance, the users report that the connections work fine for some time, but then start getting disconnected. What best practice should I follow when configuring persistence?

Cause: By default, the time-out value for Cookie Insert persistence is 120 seconds.

Resolution: When you configure persistence for applications for which idle time cannot be determined, set the Cookie Insert persistence time-out value to 0. With this setting, the connection does not time out.

After configuring an HTTP virtual server on the NetScaler appliance, I need to make sure that a user always connects to the same server for the requested content, so I configured SourceIP persistence. Now, increasing the time-out value for persistence introduces latency. How can I increase the timeout value without affecting performance?
Resolution: Consider using Cookie Insert persistence with the time-out value set to 0. This setting enables long-duration persistence settings, because the appliance does not specify a time for expiring the cookie.
After configuring Cookie Insert persistence on the NetScaler appliance, it works as expected when clients from the same time zone access the content. However, when a client from another time zone makes an attempt to connect, the connection is immediately timed out.

Cause: Time based Cookie Insert persistence works as expected when a client from the same time zone makes a connection. However, when the client machine and NetScaler appliance are in different time zones, the cookie is not valid. For example, when a client in EST time zone sends a cookie at 11:00 AM EST to a NetScaler appliance in the PST time zone, the appliance receives the cookie at 2:00 PM PST. As a result of the difference in time, the cookie is not valid, and the connection is immediately timed-out.

Resolution: Set the time-out value for Cookie Insert persistence to 0.

A NetScaler appliance is used to load balance application servers, such as Oracle Weblogic server. To make sure that clients get persistent connections to these servers, SourceIP persistence is configured. It works as expected when a connection is made from a computer. However, when thin clients attempt a connection through a terminal server and, as a result, the appliance receives requests from multiple clients from the same IP address (the terminal server IP address). Therefore, the connections from all thin clients are directed to the same application server. Is it possible to configure persistency for requests from individual thin clients based on the client IP address?

Cause: The NetScaler appliance receives requests from the terminal server and the source IP address of the request remains the same. As a result, the appliance cannot distinguish among the requests received from the thin clients and provide persistence according to the requests from thin clients.

Resolution: To avoid this problem, you can configure Rule persistence based on some unique parameter value for each thin client.

The NetScaler appliance is used to load balance Web Interface servers. When accessing the servers, the user receives the “State Error” error message. Additionally, when one of the Web Interface servers is shut down or not available, some of the users receive an error message.

Cause: Lack of persistence to the Web Interface servers can result in error messages when a user attempts to connect to the server.

Resolution: Citrix recommends that you specify the Cookie Insert persistence method on the NetScaler appliance when load balancing Web Interface servers.