One of the great features in SCOM is the ability to place a machine/device or part of it in maintenance mode whenever you are working on the machine and you do not want it to generate alerts while you are doing your stuff. For instance during a planned change. This also avoids unnecessary red and yellow health states which affect your SLA availability reports. One more thing is that it tends to not stress out helpdesks and ticketing systems if you try to avoid sending them unneeded alerts (sometimes they do not know you are playing with the machines).
In many cases a whole machine will be placed into maintenance mode. As of SCOM 2007 R2 setting maintenance mode for a machine only has to be done in one place and not in three places like before.
You can enable maintenance mode from any state view by clicking the desired machine/device/website/database and selecting Start Maintenance Mode in the actions pane or by right-clicking and selecting that option. This can also be done right from an alert view, but I always prefer to be clear on where I select it.
From there you can select if it is planned or not and what the reason is. You can start it, stop it or change the duration.
Something to NOT do is place management servers in maintenance mode. Unless you know what you are doing.
In some cases when you have a health explorer that will not turn green and manually resetting it does not help and in some cases it is just at the rollup stages where it will not turn back to green… you can try to place the machine in maintenance mode for 15 minutes and after that time it will re-calculate the health state.
In an upcoming Trick I will list some of the tools you can use for maintenance mode, scripts, powershells, management packs and so on.
Just remember to use maintenance mod.