In this case, a customer reported that the license server wasn’t releasing licenses when a render node crashed.
Why did this happen? Because the customer had an older version of the license server that didn’t have a license TIMEOUT.
Since early 2012, the Solid Angle license server ships with a default TIMEOUT of 120 seconds. That means if a workstation stops sending heartbeats to the license server, then after two minutes the license server takes back the license. So, for example, if a workstation crashes or disconnects from the network, then the license server will take back the license after a couple of minutes.
The TIMEOUT is specified in a solidangle.opt file located in the RLM folder, along with rlm.exe and solidangle.set. Newer versions of the Solid Angle license server ship with this options file, but if you don’t have it, you can either upgrade your RLM or create the file yourself. Here’s what it should look like:
TIMEOUT 120 arnold
You’ll need to restart the server to read the new options.
What are heartbeats? Heartbeats are messages sent from a licensed application to the license server while the application has one or more licenses checked out from the server. You can see them with Process Monitor. In this screenshot, you can see that XSI.exe is sending a heartbeat every one minute to the license server.
If you need to free a checked out license, you can “remove” it (that’s RLM-speak for taking back a checked out license).
To remove a license in rlm admin (localhost:5054):