DB Free Space Left

Microsoft.SQLServer.2016.Database.DBSizePercentMonitor (UnitMonitor)

Monitors the space available in the database and on the media hosting the database in percentage terms. Note: This monitor is disabled by default. Please use overrides to enable it when necessary. This monitor does not count free space for FILESTREAM and Memory-Optimized Data file groups.

Knowledge Base article:

Summary

Monitors the space available on the database and on the media hosting the database. The space available on the media hosting the database is only included as part of the space available if autogrowth is enabled for at least one of the files. Note that this monitor does not count free space for FILESTREAM and Memory-Optimized Data file groups.

Causes

An unhealthy state is caused by having low free space across all database files. Low free space can be caused by:

Use the following links to view the performance data: Database Performance Data

This monitor aggregates the space available for each file within a database depending on each file’s configuration:

No Autogrowth

For a file that has no autogrowth, free space would be the difference between the initial size for a file and the used space.

Autogrowth Enabled

In addition to the difference between the file size and the used space, the free space for files with autogrowth enabled would be the minimum of either the difference between the max size and the file size and the free space left on disk.

Low free space for database files that have autogrowth could mean that the file is approaching the limits of the hosting logical drive. For files with autogrowth enabled with a max size, low free space could also mean that the file is approaching the max size specified for a file.

The free space calculations also take into account that the file can also fail to grow if the growth amount of the file is greater than the amount left on disk and that the file cannot grow if the difference between the max size and the current file size is less than the growth amount. In these situations, available free space left on disk is not included as part of the free space because we cannot grow any longer.

Resolutions

This issue may be resolved by either:

See SQL Server Books Online: Files and Filegroups Architecture

Overrideable Parameters

Name

Description

Default Value

Alert Priority

Defines Alert Priority.

High

Alert Severity

Defines Alert Severity.

MatchMonitorHealth

Azure Maximum File Size (MB)

The maximum size of data file stored in Azure BLOB Storage. The workflow will consider this value as a maximum storage capacity for each file.

1048576

Critical Threshold

The monitor will change its state to Critical if the value drops below this threshold. Being between this threshold and the warning threshold (inclusive) will result in the monitor being in a warning state.

10

Enabled

Enables or disables the workflow.

No

Generates Alerts

Defines whether the workflow generates an Alert.

Yes

Interval (seconds)

The recurring interval of time in seconds in which to run the workflow.

900

Synchronization Time

The synchronization time specified by using a 24-hour format. May be omitted.

 

Timeout (seconds)

Specifies the time the workflow is allowed to run before being closed and marked as failed.

300

Warning Threshold

The monitor will change its state to Warning if the value drops below this threshold.

20

Element properties:

TargetMicrosoft.SQLServer.2016.Database
Parent MonitorMicrosoft.SQLServer.2016.Database.DBSpaceMonitor
CategoryPerformanceHealth
EnabledFalse
Alert GenerateTrue
Alert SeverityMatchMonitorHealth
Alert PriorityHigh
Alert Auto ResolveTrue
Monitor TypeMicrosoft.SQLServer.2016.DBAndLogSizeMonitorType
RemotableTrue
AccessibilityPublic
Alert Message
MSSQL 2016: Database is Out of Space
The database "{0}" in SQL instance "{1}" on computer "{2}" is running out of space. See "Alert Context" tab for more details.
RunAsDefault

Source Code:

<UnitMonitor ID="Microsoft.SQLServer.2016.Database.DBSizePercentMonitor" Accessibility="Public" Enabled="false" Target="SQL2016Core!Microsoft.SQLServer.2016.Database" ParentMonitorID="Microsoft.SQLServer.2016.Database.DBSpaceMonitor" Remotable="true" Priority="Normal" TypeID="Microsoft.SQLServer.2016.DBAndLogSizeMonitorType" ConfirmDelivery="false">
<Category>PerformanceHealth</Category>
<AlertSettings AlertMessage="Microsoft.SQLServer.2016.Database.DBSizePercentMonitor.AlertMessage">
<AlertOnState>Warning</AlertOnState>
<AutoResolve>true</AutoResolve>
<AlertPriority>High</AlertPriority>
<AlertSeverity>MatchMonitorHealth</AlertSeverity>
<AlertParameters>
<AlertParameter1>$Target/Property[Type="SQL2016Core!Microsoft.SQLServer.2016.Database"]/DatabaseName$</AlertParameter1>
<AlertParameter2>$Target/Host/Property[Type="SQL2016Core!Microsoft.SQLServer.2016.ServerRole"]/InstanceName$</AlertParameter2>
<AlertParameter3>$Target/Host/Host/Property[Type="Windows!Microsoft.Windows.Computer"]/NetworkName$</AlertParameter3>
</AlertParameters>
</AlertSettings>
<OperationalStates>
<OperationalState ID="UnderThreshold1" MonitorTypeStateID="UnderThreshold1" HealthState="Error"/>
<OperationalState ID="OverThreshold1UnderThreshold2" MonitorTypeStateID="OverThreshold1UnderThreshold2" HealthState="Warning"/>
<OperationalState ID="OverThreshold2" MonitorTypeStateID="OverThreshold2" HealthState="Success"/>
</OperationalStates>
<Configuration>
<IntervalSeconds>900</IntervalSeconds>
<SyncTime/>
<ConnectionString>$Target/Host/Property[Type="SQL2016Core!Microsoft.SQLServer.2016.DBEngine"]/ConnectionString$</ConnectionString>
<ServerName>$Target/Host/Host/Property[Type="Windows!Microsoft.Windows.Computer"]/NetworkName$</ServerName>
<SqlInstanceName>$Target/Host/Property[Type="SQL2016Core!Microsoft.SQLServer.2016.ServerRole"]/InstanceName$</SqlInstanceName>
<ObjectName>SQL Database</ObjectName>
<CounterName>DB Available Space Total (%)</CounterName>
<InstanceName/>
<DatabaseName>$Target/Property[Type="SQL2016Core!Microsoft.SQLServer.2016.Database"]/DatabaseName$</DatabaseName>
<Value>$Data/Property[@Name='DBFreeSpacePercent']$</Value>
<Threshold1>10</Threshold1>
<Threshold2>20</Threshold2>
<TimeoutSeconds>300</TimeoutSeconds>
<AzureMaxFileSizeMB>1048576</AzureMaxFileSizeMB>
</Configuration>
</UnitMonitor>