Maintenance windows are important for normal data center operations. Maintenance periods provide vital opportunities to patch, upgrade, reconfigure or simply inspect servers. However, taking servers offline -- even for the most mundane reasons -- can precipitate unnecessary alarms, trigger log errors, and cause inaccurate assessments of system availability or uptime. Management tools like System Center 2012 Configuration Manager support maintenance windows, which allow select groups of servers to temporarily be removed from monitoring. Administrators can then work with those systems without unwanted alarms or inconsequential log errors.
Once you've successfully inventoried all of the servers, SCCM 2012 can use direct- or query-based collections to include Linux, UNIX and Windows servers in maintenance windows. Once a maintenance window is invoked, SCCM can help with software deployments or updates, security settings to address compliance or other concerns, operating system updates and a variety of other tasks.
SCCM 2012 includes Linux and UNIX servers in the "All Systems" collection by default, and this is probably not appropriate for all maintenance window tasks. For example, a typical maintenance window might be used to patch operating systems, but patching a Linux distribution to a mixed (Windows/Linux) server collection might cause the patch deployment to be reported as unsuccessful (because the Windows servers in the collection would not be updated with Linux patches). A best practice is usually to keep Linux systems in a separate collection so that any Linux-specific task outcomes will be reported successfully.
It is possible to include the same computer in multiple collections, and each collection can be assigned a different maintenance window. This means the same system could potentially have more than one maintenance window. Multiple maintenance windows are not necessarily an error or oversight -- multiple windows can be used to help administrators organize different maintenance tasks. For example, Linux systems might be included in one collection in order to support Linux distribution patches or updates. Yet a Linux, UNIX or Windows server could also be mixed into collections intended to facilitate other tasks, such as server hardware maintenance, handled on different days and times.
If a server is subject to multiple maintenance windows that do not overlap, the maintenance windows are regarded as separate events. If the server is subject to multiple maintenance windows that do overlap, the window is treated as a single event that is only as long as the two windows -- minus the overlap. For example, if two 30-minute maintenance windows overlap by 10 minutes, SCCM 2012 regards this as a single 50-minute window.
How to use SCCM collections with Linux