Challenge: How to solve the Citrix “Black Hole” problem.

The Citrix “Black Hole” problem occurs when a large number of users are directed to a specific Citrix server within a short period of time. This situation can be caused by a new server coming online in the Citrix farm. As the server becomes available, the load balancer sees that this new server’s load is much less than the other servers in the farm and, at this point, the load balancer may start to send all new users to the server that just came online. This flood of new users often times overwhelms the server.

The Solution: RTO PinPoint™.

One of the unique metrics provided by RTO PinPoint shows the increase in the number of users for a Citrix server over the last minute. This important measurement can point out when there is a large increase in users being sent to a Citrix server. By setting an alert the administrator can be immediately notified when this metric shows a large increase. Setting threshold values in the PinPoint console provides the ability to customize when an administrator should be notified.

The administrator can also configure PinPoint to run a script when an alert is received. Scripts can be written to automatically perform actions such as stopping new logons to the server for a period of time, or other appropriate actions. Using PinPoint in this manner keeps your administrators “in the know” and helps avoid the performance pitfalls that can be caused by the “Black Hole”.