Redundant Server Setup With MES

If I want to set up a redundant server setup including the MES Module, do I need to have two MES licences?
Or can the redundant system work if I only have one MES licence, ie. the MES module on the Backup server will be in trial mode only, so the client will only have access to MES when the Master server is ok.

Sorry for taking so long to answer this.

For redundancy you will need an MES module license for each server. You do not need to purchase the cells or locations portions of the license for the backup server though.
Your sales rep will be able to give you an accurate quote for a redundant system.

If you only have one MES license the redundant system will “work” but it cannot do state synchronization. In effect it is not a redundant system for MES.