HyperFS uses a centralized client license method, where only the license file of the active MDC is checked for a given number of concurrent SAN clients. There is no license that goes on any client machine.
The concurrent license seats are checked in real time by the active MDC. For example, if the license is for 10 client seats, and 10 clients are currently mounted, an attempt to mount an 11th machine will give an error. Should one of the original 10 clients be unmounted, a seat is then freed, the used seats will drop to 9, and a different 10th client may be mounted.
Additionally, in high-availability (HA) environments, there will be an active/passive pair of HyperFS MDCs, each with a unique hardware signature. If additional license capabilities, such as additional client seats, are purchased, you must be sure to update the respective license on each server. Both the hardware signature as well as the corresponding license are unique to an individual hardware server, and may not be swapped.
Reinstall of the MDC OS doesn't break the license, the hardware signature and corresponding license file will remain the same. Replacing a MB will require getting a new license as the hardware signature will change. Contact Scale Logic in this event.