One of the many monitoring probes in Managed Availability is the ability to monitor the free space on drives that house Exchange databases.
By default the free space threshold is 200GB. Because many people regularly went under this metric on free space many administrators simply set an override on the monitoring probe to turn it off altogether. Effectively removing the probe altogether and not report on free space at all.
Pre-SP1 the command to override the monitoring probe was:
Add-ServerMonitoringOverride -Identity "MailboxSpace\StorageLogicalDriveSpaceEscalate" -Server 'server' –ItemType "Responder" -PropertyName Enabled -PropertyValue 0
However in Exchange 2013 SP1 this command has changed and is now based on the 'Add-GlobalMonitoringOverride' cmdlet. So many administrators found with new SP1 deployments they could no longer turn the probe off.
The new command for SP1 is:
Add-GlobalMonitoringOverride -Identity "MailboxSpace\StorageLogicalDriveSpaceEscalate" -ItemType "Responder" -PropertyName Enabled -PropertyValue 0 -ApplyVersion "15.0.847.32"
Note: you must always use -ApplyVersion which applies an unlimited duration to the server version that matches the output, otherwise you need to specify -Duration which has a maximum application of 90 days.
A fantastic inclusion in SP1 is also the ability to change the default 200GB free space setting. You can now customize this to a size of your choosing by adding the following reg key:
This will allow you to set a more 'real world' value for your environment and taylor the metric to your environments needs. As an example if you are using 500GB disks and you manage your Exchange organisaton well, you may very well want the setting well below the default 200GB threshold. Allowing you to keep the monitoring probe enabled and in use.
Oliver Moazzezi - MVP Exchange Server