Monitors the space available in log files
Monitors the space available on the log files and on the media hosting the log files. The space available on the media hosting the log files is only included as a part of the space available if auto grow is enabled for at least one of the files.
Unhealthy state is caused by low space free space across all log files. Low free space can be caused by:
Inadequate file configuration settings (size, max size, auto grow, etc.)
Inadequate space left on the media
Lack of periodic regular backups
Log not truncating
This monitor aggregates the space available for each log file within a database depending on each file configuration:
No Auto Grow
For a file that has no auto grow, free space would be the difference between the initial size for a file and the used space.
Auto Grow Enabled
In addition to the difference between the file size and the used space, the free space for files with auto grow 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 auto grow could mean that the file is approaching the limits of the hosting logical drive. For files with auto grow 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 a 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 auto grow is disabled
Increasing the max size value for a log file if auto grow is enabled
Enabling auto grow 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 the 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)
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. | MatchMonitorHealth |
Enabled | Enables or disables the workflow. | Yes |
Generates Alerts | Defines whether the workflow generates an Alert. | Yes |
Target | Microsoft.SQLServer.2008.Database | ||
Parent Monitor | Microsoft.SQLServer.2008.Database.DBLogFileSpaceMonitor | ||
Algorithm | BestOf | ||
Source Monitor | Microsoft.SQLServer.2008.Monitoring.DBLogFileSpaceMonitor | ||
Relationship | Microsoft.SQLServer.2008.DBHostsLogFile | ||
Category | PerformanceHealth | ||
Enabled | True | ||
Alert Generate | True | ||
Alert Severity | MatchMonitorHealth | ||
Alert Priority | Normal | ||
Alert Auto Resolve | True | ||
Remotable | True | ||
Accessibility | Public | ||
Alert Message |
|
<DependencyMonitor ID="Microsoft.SQLServer.2008.Database.DBLogFileSpaceMonitorRollUp" Accessibility="Public" Enabled="true" Target="SQL2008Core!Microsoft.SQLServer.2008.Database" ParentMonitorID="Microsoft.SQLServer.2008.Database.DBLogFileSpaceMonitor" Remotable="true" Priority="Normal" RelationshipType="SQL2008Core!Microsoft.SQLServer.2008.DBHostsLogFile" MemberMonitor="Microsoft.SQLServer.2008.Monitoring.DBLogFileSpaceMonitor">
<Category>PerformanceHealth</Category>
<AlertSettings AlertMessage="Microsoft.SQLServer.2008.Database.DBLogFileSpaceMonitorRollUp.AlertMessageResourceID">
<AlertOnState>Warning</AlertOnState>
<AutoResolve>true</AutoResolve>
<AlertPriority>Normal</AlertPriority>
<AlertSeverity>MatchMonitorHealth</AlertSeverity>
<AlertParameters>
<AlertParameter1>$Target/Property[Type="SQL!Microsoft.SQLServer.Database"]/DatabaseName$</AlertParameter1>
<AlertParameter2>$Target/Host/Property[Type="SQL!Microsoft.SQLServer.ServerRole"]/InstanceName$</AlertParameter2>
<AlertParameter3>$Target/Host/Host/Property[Type="Windows!Microsoft.Windows.Computer"]/NetworkName$</AlertParameter3>
</AlertParameters>
</AlertSettings>
<Algorithm>BestOf</Algorithm>
<MemberUnAvailable>Error</MemberUnAvailable>
</DependencyMonitor>