IBM Support

Delay of the License checkout: Slow performance



This technote describes an issue that might be observed during the license checkout on a FLEXlm license server for Rational products.


The time between asking for a license and getting a license could be about 40 milliseconds while in normal cases this should not be more than 5 - 10 milliseconds.


For a large number of clients (who are each exchanging heartbeat messages with the server), or for high checkout/checkin activity levels (hundreds per second), the amount of CPU time consumed by the server may start to become significant, although, even here, CPU usage is normally not high. In this case, you might need to ensure that the server machine you select has enough CPU cycles to spare.

For small numbers of clients, the license server systems use very little CPU time. The servers might have only a few seconds of CPU time after many days.

The FLEXnet license server system uses little memory. On SunOS, lmgrd uses approximately 2 MB, and the vendor daemons use approximately 2 MB each, although memory usage increases in the vendor daemon with the size of the license file, size of the options file, and the number of concurrent users.

Resolving The Problem

As long as the license keys are served and no error message is generated the license server is running as designed and no change is required.

You might need to clean the report log file.The report log files are used to generate accurate usage reports by FLEXnet. If you have a lot of license activity, these log files grow very large. You need to consider where to put these files and how often to rotate and archive them. The license administrator has the option to suppress log file output if disk space is at a premium. It is recommended that the log files are local files on the server machines to avoid networking dependencies.

[{"Product":{"code":"SSTMW6","label":"Rational License Key Server"},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Component":"FLEXlm","Platform":[{"code":"PF002","label":"AIX"},{"code":"PF010","label":"HP-UX"},{"code":"PF016","label":"Linux"},{"code":"PF027","label":"Solaris"},{"code":"PF033","label":"Windows"}],"Version":"2003.06.16;7.0;;;7.0.1;;7.1","Edition":"","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
27 December 2019