Redundant server configuration

This configuration is supported on UNIX only.  

A redundant server configuration designates a set of three server nodes to serve the same license file. The license file contains three SERVER lines.  The license manager (lmgrd) is started on all three nodes. To set up redundant servers, you must provide ESRI Customer Service with the hostids for all three servers.

No licenses are available until there is a quorum of two servers available. One server is designated 'master' and issues the licenses. The master server is selected from the first two servers to connect with each other. From these two servers, the master is always the server listed first in the license file.

If the master server goes down, another server becomes master. When one server goes down, the two remaining servers MUST remain running. If either goes down, licenses are denied.  The reliability of the system is dependent on BOTH servers. Therefore, the administrator must detect when one or more of the three servers are down and bring it or them back up as soon as possible.

ESRI strongly discourages the use of the redundant server configuration, as does GLOBEtrotter, the manufacturer of FLEXlm software.  The redundant server configuration does not save time or effort. When one or more of the redundant servers go down, the same amount of manual administration is required as when one or more independent license servers go down. You must still reroute your end-users to alternate servers.  To reroute end-users on UNIX, you must change the location of their variable settings of $ARCHOME and $SDEHOME. On Windows, each end-user will have to change the license manager setting in their Desktop Administrator.  

Alternatively, you can split up your licenses among multiple independent servers. This is easier to administer and still allows a portion of the licenses available when one server goes down.