Topic Last Modified: 2010-08-13
The Microsoft Exchange Server 2010 Management Pack for System Center Operations Manager includes a performance data collection engine that is used to query performance counter objects on computers running Exchange 2010. For this Operations Manager rule, data is collected by using the performance counter specified in the Details table.
To review the value of the performance counter that generated this alert, in Operations Manager, double-click this alert, and then click the General tab. Review the description of the alert that includes the variables specific to your environment.
14.0 (Exchange 2010)
% Free Space
Microsoft Exchange Server/Exchange 2010/Mailbox/Public Folder Database Log Logical Disk Space
The database copy is low on log volume space. The volume has reached error levels (35% free).
This alert indicates that a replication issue may affect the mailbox database copies in a particular Exchange Server 2010 database availability group (DAG).
Microsoft Exchange Server 2010 uses continuous replication to create and maintain database copies. To maintain a synchronized copy of a mailbox database, transaction log files from the active mailbox server are replayed into the passive database of another server in the DAG. This provides high availability and resiliency in the Exchange environment.
The information store is responsible for replaying the log file for the passive copy of the database that is hosted on a server. When a replica instance of a copied database is started, the Replay service contacts the information store and creates an ESE instance for the database to be mounted. This mount is for log replay only. The Replay service Log Replayer component then contacts the store over the RPC STORE ADMIN Interface (ExRpcAdmin.LogReplayRequest) to pass the log files that have to be replayed by the store.
If the volume that hosts the passive database copy runs out of disk space, transaction logs can no longer be played to the database. In this scenario, the passive database copy status changes to Failed, and the database copy will no longer be synchronized with the active mailbox database.
A warning (Yellow) alert is generated when the Windows Reliability and Performance Monitor LogicalDiskSpace\% Free Space object has a value that is less than 50 percent. When the object's value is less than 35 percent, a severe problem (Red) alert is generated.
To resolve this error, do one or more of the following:
- Review the Application log and System log on your Exchange 2010
servers for related events. For example, events that occur
immediately before and after this event may provide more
information about the root cause of this error.
- Review Operations Manager for detailed information about the
cause of this problem. For more information, see the "Introduction"
section in this article.
- Check the following performance counter by using Windows
Reliability and Performance Monitor:
- Object: LogicalDiskSpace\% Free Space
- Object: LogicalDiskSpace\% Free Space
- Examine the network topology between any connected storage that
may be used for the log file location to determine whether the Log
Replayer can write the changes to the passive database quickly
- Examine the System log to determine whether any issues are
affecting the disk subsystem.
- Examine the CPU usage of the Store.exe process to determine
whether an issue is affecting the information store on the passive
- Move the transaction log storage location to a faster disk
subsystem. RAID arrays are not required for use together with
- Move the transaction log storage location to a larger
- Examine the memory and CPU usage on the passive mailbox server
to determine whether a memory bottleneck is causing additional disk
- Determine whether the LogTruncationExtendedPreservation
registry entry has been set to a high value. This registry entry
forces the log truncator to preserve additional transaction log
files. The value must be a positive integer. It specifies the
number of logs that will be retained, even though the logs are not
required. The default value is 10. The registry entry is
located in the following registry subkey:
- Examine the current replication status for each replica
database. To do this, use the Get-MailboxDatabaseCopyStatus
cmdlet. This cmdlet returns information about all copies of a
particular database, information about a specific copy of a
database on a specific server, or information about all database
copies on a server.
For more information, see the following topics in Exchange 2010 Help:
- Understanding Mailbox Database Copies
- Understanding Database Availability Groups
For More Information
If you are not already doing so, consider running the Exchange tools created to help you analyze and troubleshoot your Exchange environment. These tools can help make sure that your configuration aligns with Microsoft best practices. They can also help you identify and resolve performance issues, improve mail flow, and better manage disaster recovery scenarios. To run these tools, go to the Toolbox node of the Exchange Management Console. To learn more about these tools, see Managing Tools in the Toolbox.