If a multiplex secondary server will be shut down for an extended period of time, exclude that server from the multiplex.
Excluding a server allows the coordinator to ignore that server when performing version cleanup. Otherwise, the coordinator will need to reserve all old versions of IQ objects since the secondary node was shut down. This takes up unnecessary disk space. A designated failover server cannot be excluded unless it is the last secondary node to be excluded in the multiplex. Include/exclude does not apply to the coordinator.
An alternate method is to right-click the server and select context menu Control > Include/Exclude.