Mail Database

This resource contains performance counters specific to the status of the current Mail Database. The icons of the listed performance counters in the Statistic Name column change colors to reflect the listed counter's current state. Clicking any performance counter in the Statistic Name column takes you to the Performance Counter Details page for that performance counter.

If the value of a listed performance counter crosses the Warning threshold, the chart for the listed counter displays a yellow background. If the value of a listed monitor crosses the Critical threshold, the chart for the listed counter displays a red background. Hovering over any time period within the chart displays detailed information about that time period in the tooltip. Hovering over a counter gives you detailed information about that performance counter.

The following table lists the default performance counters for this resource along with their respective definitions and troubleshooting information, including default Warning and Critical thresholds:

Counter Expert Knowledge

Warn-ing

Criti-
cal

Database Cache Size (MB)

Definition:
Shows the amount of system memory, used by the database cache manager to hold commonly used information from the database files to prevent file operations.

Information: 
This and Database Cache Hit % are useful counters for gauging whether a server's performance problems might be resolved by adding more physical memory. Use this counter along with store private bytes to determine if there are store memory leaks.

Possible problems: 
Situation when the database cache size seems too small for optimal performance and there is little available memory on the system (check the value of Memory/Available Bytes) could negatively impact on performance. If there is ample memory on the system and the database cache size is not growing beyond a certain point, the database cache size may be capped at an artificially low limit. Increasing this limit may increase performance.

Remediation: 
Adding more memory to the system and/or increasing database cache size may increase performance.

N/A

N/A

Database Page Fault Stalls/sec

Definition:
Shows the rate that database file page requests require of the database cache manager to allocate a new page from the database cache.

Information: 
Should be 0 at all times.

Possible problems: 
If this value is nonzero, this indicates that the database is not able to flush dirty pages to the database file fast enough to make pages free for new page allocations.

Remediation:
If the disk subsystem is not meeting demand, correcting the problem may require additional disks, faster disks, or modifying the disk configuration.

> 0 

> 0 for 15 polls

Version Buckets Allocated

Definition:
Shows the total number of version buckets allocated.

Information: 
Should be less than 12,000 at all times. The maximum default version is 16,384. If version buckets reach 70% of maximum, the server is at risk of running out of the version store.

Possible problems: 
Typically indicates a database transaction which is taking a long time to save to disk. During Online DB defrags, the version buckets may increase.

Remediation:
Verify if the server has any applications running that have a long running transaction which has not been saved to disk, causing the version store memory resource to be exhausted.

> 11500 

> 12000

Log Record Stalls/sec

Definition:
Shows the number of log records that can't be added to the log buffers per second because the log buffers are full. If this counter is nonzero for a long period of time, the log buffer size may be a bottleneck.

Information: 
The average value should be below 10 per second. Spikes (maximum values) should not be higher than 100 per second.

Possible problems: 
If I/O log write latencies are high, check for RAID5 or synchronize replication on log devices.

Remediation:
You can also use the MSExchange Database Instances (Information store/<Database Name>)\log record stalls/sec counter to determine which database(s) may be having issues. This assists you in determining which drive(s) to focus on. This counter is an extended Exchange counter in Performance Monitor. The solution can include additional disks, reconfigured RAID configuration, adding new database(s), or re-balancing mailboxes across databases or servers.

> 10 for 15 polls

> 10 for 60 polls 

Log Threads Waiting

Definition:
Shows the number of threads waiting for their data to be written to the log to complete an update of the database. If this number is too high, the log may be a bottleneck.

Information: 
Should be less than 10 on average.

Possible problems: 
If this number is too high, the log may be a bottleneck. Regular spikes concurrent with log record stall spikes indicate that the transaction log disks are a bottleneck. If the value for log threads waiting is more than the spindles available for the logs, there is a bottleneck on the log disks.

Remediation:
If the disk subsystem is not meeting demand, correcting the problem may require additional disks, faster disks, or modifying the disk configuration.

> 10 for 15 polls

> 10 for 60 polls 

Zooming

You can have the chart show a predetermined time period of data by clicking on any one of the three Zoom buttons in the head of the Zoom column. Alternatively, you can have the chart show a specific date range by dragging the mouse over an area of the chart. The time and date displayed at the top of the resource shows the amount of data currently loaded into the chart. This can be changed by clicking Edit from within the resource.

The Value from Last Poll column shows the most recent data available for the listed statistic.

Additional components on certain resources may be available for addition and/or deletion on the Edit page.