Transaction Log Space Free (MB)

Microsoft.SQLServer.2008.Database.TransactionLogSizeMegabytesMonitor (UnitMonitor)

Monitors for the free space left in the transaction log in percentage terms.

Knowledge Base article:

Summary

This monitor checks the transaction log absolute free space in Megabytes to ensure it is above the defined thresholds. A warning or error alert will be raised if it is below one of the defined thresholds.

Transaction logs that have autogrow set will never generate an alert regardless of the reported free space.

Out of the box, this monitor will never cross a threshold as both thresholds are set to -1. Monitoring using percentage free space is the default behavior. If it is required to monitor using absolute free space, the threshold values for this monitor should be overridden

Causes

An unhealthy state is caused by the transaction log running low on free space. This could be due to rapid growth or may have been developing slowly over time. Use the following link to view the historic data for this database:

Database Performance Data

Resolutions

This issue may be resolved by either:

Allocating more storage for the transaction log
Setting at least one file to autogrow for the transaction log

Alternatively if transaction log size is not a concern for this database:

Change the thresholds on the monitor for this specific database or all databases
Disable the monitor for this specific database or all databases

Element properties:

Target

Microsoft.SQLServer.2008.Database

Parent Monitor

System.Health.PerformanceState

Category

PerformanceHealth

Enabled

False

Alert Generate

True

Alert Severity

MatchMonitorHealth

Alert Priority

Normal

Alert Auto Resolve

True

Monitor Type

Microsoft.SQLServer.2008.DBAndLogSizeMonitorType

Remotable

True

Accessibility

Public

Alert Message

Transaction Log Space Free (MB)

Database {2} in SQL Server instance {1} on computer {0} is running low on transaction log free space

RunAs

Default

Source Code:

<UnitMonitor ID="Microsoft.SQLServer.2008.Database.TransactionLogSizeMegabytesMonitor" Accessibility="Public" Enabled="false" Target="SQL2008Core!Microsoft.SQLServer.2008.Database" ParentMonitorID="SystemHealth!System.Health.PerformanceState" Remotable="true" Priority="Normal" TypeID="Microsoft.SQLServer.2008.DBAndLogSizeMonitorType" ConfirmDelivery="false">

  <Category>PerformanceHealth</Category>

  <AlertSettings AlertMessage="Microsoft.SQLServer.2008.Database.TransactionLogSizeMegabytesMonitor.AlertMessage">

    <AlertOnState>Warning</AlertOnState>

    <AutoResolve>true</AutoResolve>

    <AlertPriority>Normal</AlertPriority>

    <AlertSeverity>MatchMonitorHealth</AlertSeverity>

    <AlertParameters>

      <AlertParameter1>$Target/Host/Host/Property[Type="Windows!Microsoft.Windows.Computer"]/NetworkName$</AlertParameter1>

      <AlertParameter2>$Target/Host/Property[Type="SQL!Microsoft.SQLServer.ServerRole"]/InstanceName$</AlertParameter2>

      <AlertParameter3>$Target/Property[Type="SQL!Microsoft.SQLServer.Database"]/DatabaseName$</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>$Target/Host/Property[Type="SQL!Microsoft.SQLServer.DBEngine"]/ConnectionString$</ConnectionString>

    <ObjectName>$Target/Host/Property[Type="SQL!Microsoft.SQLServer.DBEngine"]/PerformanceCounterObject$:Database</ObjectName>

    <CounterName>Log Free Space (MB)</CounterName>

    <InstanceName>$Data/Property[@Name='Database']$</InstanceName>

    <DatabaseName>$Target/Property[Type="SQL!Microsoft.SQLServer.Database"]/DatabaseName$</DatabaseName>

    <Value>$Data/Property[@Name='TransactionLogFree']$</Value>

    <Threshold1>-1</Threshold1>

    <Threshold2>-1</Threshold2>

    <AutoGrowSet>$Target/Property[Type="SQL!Microsoft.SQLServer.Database"]/LogAutogrow$</AutoGrowSet>

    <TimeoutSeconds>300</TimeoutSeconds>

  </Configuration>

</UnitMonitor>