Transaction Log Free Space (\%) monitor for 2016 databases. Note: This monitor is disabled by default. Please use overrides to enable it when necessary.
Transaction Log Free Space (%) monitor for SQL 2016 DB
An unhealthy state is caused by having low free space across all log files. Low free space can be caused by:
Inadequate file configuration settings (size, max size, autogrowth, etc.)
Inadequate space left on media
Lack of periodic regular backups
Log not truncating
The “Include Disk Space” setting for this monitor is set to FALSE for workloads that expect their files to grow.
Use the following link to view the performance data:
Database Performance Data
This monitor aggregates the space available for each log 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 log 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.
This issue may be resolved by either:
Increasing the allocated size for log files if autogrowth is disabled
Increasing the max size value for a log file if autogrowth is enabled
Enabling autogrowth for at least one file
Moving log files to another drive with more free space if growth space is limited
Performing regular backups of log files for FULL and BULK-LOGGED recovery modes
Investigate why log is not getting truncated:
Long open running active transactions
Long running backup operations
Replicated transaction open for a long time (Transactional Replication)
Mirror lagging behind principal server (Database Mirroring)
Set the “Include Disk Space” setting for this monitor to TRUE for workloads that expect their files to grow
Modifying the thresholds for this monitor to suit the workload
Alternatively if log file free space is not a concern for the database:
Disable this monitor for this specific database or all databases
See SQL Server Books Online: Files and Filegroups Architecture
Name | Description | Default Value |
Alert Priority | Defines Alert Priority. | Normal |
Alert Severity | Defines Alert Severity. | Error |
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 |
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. | 300 |
Number of samples | Indicates how many times a measured value should breach a threshold before the state is changed. | 6 |
Threshold | The collected value will be compared against this parameter. | 10 |
Timeout (seconds) | Specifies the time the workflow is allowed to run before being closed and marked as failed. | 180 |
Target | Microsoft.SQLServer.2016.Database | ||
Parent Monitor | Microsoft.SQLServer.2016.Database.DBSpaceMonitor | ||
Category | PerformanceHealth | ||
Enabled | False | ||
Alert Generate | True | ||
Alert Severity | Error | ||
Alert Priority | Normal | ||
Alert Auto Resolve | True | ||
Monitor Type | Microsoft.SQLServer.2016.Database.TransactionLogSpaceFreePercent.MonitorType | ||
Remotable | True | ||
Accessibility | Public | ||
Alert Message |
| ||
RunAs | Default |
<UnitMonitor ID="Microsoft.SQLServer.2016.Database.TransactionLogSpaceFreePercentMonitor" Accessibility="Public" Enabled="false" Target="SQL2016Core!Microsoft.SQLServer.2016.Database" ParentMonitorID="Microsoft.SQLServer.2016.Database.DBSpaceMonitor" Remotable="true" Priority="Normal" TypeID="Microsoft.SQLServer.2016.Database.TransactionLogSpaceFreePercent.MonitorType" ConfirmDelivery="false">
<Category>PerformanceHealth</Category>
<AlertSettings AlertMessage="Microsoft.SQLServer.2016.Database.TransactionLogSpaceFreePercentMonitor.AlertMessage">
<AlertOnState>Error</AlertOnState>
<AutoResolve>true</AutoResolve>
<AlertPriority>Normal</AlertPriority>
<AlertSeverity>Error</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>
<AlertParameter4>$Data/Context/SampleValue$</AlertParameter4>
</AlertParameters>
</AlertSettings>
<OperationalStates>
<OperationalState ID="Normal" MonitorTypeStateID="Normal" HealthState="Success"/>
<OperationalState ID="Error" MonitorTypeStateID="Error" HealthState="Error"/>
</OperationalStates>
<Configuration>
<IntervalSeconds>300</IntervalSeconds>
<TimeoutSeconds>180</TimeoutSeconds>
<Threshold>10</Threshold>
<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>
<DatabaseName>$Target/Property[Type="SQL2016Core!Microsoft.SQLServer.2016.Database"]/DatabaseName$</DatabaseName>
<AzureMaxFileSizeMB>1048576</AzureMaxFileSizeMB>
<NumSamples>6</NumSamples>
</Configuration>
</UnitMonitor>