Bruno...
The triad server is the backup plan. As you know, if the customer doesn't want to use the triad, then using the out of the box functionaliity only offers a single license server as an alternative. But let's discuss this further...
First- unless this is a customer concerned with national security, why in the world would their server be crashing to the point that they need some type of instantt backup? In my experience, properly maintained servers don't just "go down". Second, if the customer does have this type of transient network/server environment, just use the triad! The other two servers in the triad don't have to be "server quality machines", they just have to be connected into the network and be running. They can be old and slow but as long as they're connected and running, they should perform as needed.
So I guess what I'm saying is... I'd push back a little and ask the customer why the triad isn't an option. The triad isn't perfect... but it is very useful. I understand no one ever wants to question the customer's infinite wisdom but sometimes the customer doesn't know any better and needs to be (gently) educated without offending them.
But moving on... when you start Pro/ENGINEER or Creo, there are .psf files that contain the name of the license server(s) you're using. It would totally be possible to have a duplicate set of license files pointing to a secondary server as a backup. I'd say this is actually very, very easy to do... but there's one massive catch! PTC must generate a license file for you... and that license file is generated based upon the MAC address of the server. So even if you were to install the license files onto a secondary server- and then create a separate launch script to point to the secondary server, the license file wouldn't work!!
You could ask PTC for a license file configured for a secondary server name... and I'm sure they'll ask you to pay for the additional licenses. If PTC gives you two identical license files for two separate servers, nothing stops you from using BOTH simultaneously, paying for one set of licenses and getting a second set free. I don't think they're going to do that!
Therefore... we're back to the original statement... use the Triad.
Beyond that, I don't know what else to suggest. I'm sure some well-intentioned administrator has already tried running a virtual machine as a license server. I'm sure there are restrictions or problems with this approach, too... hence the use of the MAC address in generating license files.
There is no way to automatically "borrow" a license if the server dies. Beyond giving all users locked license files, I don't know of another way around the problem. It seems the customer wants an immediate fall-over backup system and therefore, should simply implement the triad system or else make darn good and sure the primary server is professionally maintained.
Thanks!
-Brian
