Are you looking for a quick way to get all of your servers into maintenance mode without putting any of the Operations Manager servers into maintenance? While there are a variety of great methods available to provide regularly scheduled maintenance mode within Operations Manager, the question was asked for how to do this for all servers (except Operations Manager servers) on an ad-hoc basis. To do this open the Operations Console to the Windows computer view, scope to agent managed computer group.
The resulting list shows all agent managed computers which will remove the root management server and management servers from the view. Next highlight all servers except those currently in maintenance mode, right-click and put them into maintenance mode.
Voila! This doesn’t put entities such as agentless systems (clusters and such) and perspectives (synthetic transactions) into maintenance mode but it’s a quick way to get the majority of what’s needed under maintenance!