FLEXlm controls the total number of hosts configured in all your LSF clusters. You can organize your hosts into clusters however you choose. The DEMO license allows you to try LSF out on an unlimited number of hosts on any supported host type. The trial period has a fixed expiry date, and the LSF software will not function after that date. DEMO licenses do not require any additional daemons.
Permanent licenses are the most common.
A permanent license limits only the total number of hosts that can run the LSF software, and normally has no time limit. You can choose which hosts in your network will run LSF, and how they are arranged into clusters. Permanent licenses are counted by a license daemon running on one host on your network. For permanent licenses, you need to choose a license server host and send hardware host identification numbers for the license server host to your software vendor. The vendor uses this information to create a permanent license that is keyed to the license server host.