Mailbox Server Counters

 

Applies to: Exchange Server 2010 SP2, Exchange Server 2010 SP3

This topic describes performance and scalability counters relevant to the Mailbox server role in Microsoft Exchange Server 2010. You can use Performance Monitor (perfmon.exe) to monitor these counters. For more information, see Performance Monitor Getting Started Guide. For information about other counters relevant to Exchange 2010, see Performance and Scalability Counters and Thresholds.

Active Database Copy I/O Latency Requirements Counters

The following table shows active database copy input/output (I/O) latency requirements counters. When these values are exceeded, the client experience degrades. For example, users may experience slow system performance and message delivery delays.

Counter	Description	Threshold	Troubleshooting
MSExchange Database\I/O Database Reads (Attached) Average Latency	Indicates the average time, in milliseconds (ms), to read from the database file.	The average value should be below 20 ms. Spikes (maximum values) shouldn't be higher than 100 ms.
MSExchange Database\I/O Database Writes (Attached) Average Latency	Indicates the average time, in ms, to write to the database file. This counter isn't a good indicator for client latency because database writes are asynchronous.	In general, this latency should be less than the MSExchange Database\I/O Database Reads (Attached) Average Latency when battery-backed write caching is utilized.
Database\Database Page Fault Stalls/sec	Indicates the rate of page faults that can't be serviced because there are no pages available for allocation from the database cache.	This counter should be 0 on production servers.	If this counter is above 0, it's an indication that the MSExchange Database\I/O Database Writes (Attached) Average Latency is too high.

Active Log I/O Latency Requirements Counters

The following table shows active log I/O latency requirements counters. When these values are exceeded, the client experience degrades. For example, users may experience slow system performance and message delivery delays.

Counter	Description	Threshold	Troubleshooting
MSExchange Database\IO Log Writes Average Latency	Indicates the average time, in ms, to write a log buffer to the active log file.	This counter should be 10 on production servers.	If this counter is greater than 10, it's an indication that the MSExchange Database\I/O Database Writes (Attached) Average Latency is too high.
Database\Log Record Stalls/sec	Indicates the number of log records that can't be added to the log buffers per second because the log buffers are full.	The average value should be below 10 per second. Spikes (maximum values) shouldn't be higher than 100 per second.
Database\Log Threads Waiting	Indicates the number of threads waiting to complete an update of the database by writing their data to the log.	The average value should be less than 10 threads waiting.

Passive Database Copy I/O Latency Requirements Counters

The following table shows passive database copy I/O latency requirements counters. When these values are exceeded, the database copy may lag by not replaying logs to the passive database copy fast enough. Log replication performance may also be affected.

Counter	Description	Threshold	Troubleshooting
MSExchange Database\I/O Database Reads (Recovery) Average Latency	Indicates the average time, in ms, to read from the database file.	The average value should be below 200 ms. Spikes (maximum values) shouldn't be higher than 1,000 ms.
MSExchange Database\I/O Database Writes (Recovery) Average Latency	Indicates the average time, in ms, to write to the database file.	In general, this latency should be less than the MSExchange Database\I/O Database Reads (Recovery) Average Latency when battery-backed write caching is utilized.
Database\Database Page Fault Stalls/sec	Indicates the rate of page faults that can't be serviced because there are no pages available for allocation from the database cache.	This counter should be 0 on production servers.	If this counter is greater than 0, it's an indication that the MSExchange Database\I/O Database Writes (Attached) Average Latency is too high.

Replay Log I/O Latency Requirements Counter

The following table shows a replay log I/O latency requirements counter. When these values are exceeded, the database copy may lag by not replaying logs to the passive database copy fast enough. Log replication performance may also be affected.

Counter	Description	Threshold
MSExchange Database\IO Log Read Average Latency	Indicates the average time, in ms, to read data from a log file. Specific to log replay and database recovery operations.	The average value should be below 200 ms. Spikes (maximum values) shouldn't be higher than 1,000 ms.

Information Store RPC Processing Counters

The following table shows information store RPC processing counters.

Counter	Description	Threshold	Troubleshooting
MSExchangeIS\RPC Requests	Indicates the overall RPC requests currently executing within the information store process.	Should be below 70 at all times.
MSExchangeIS\RPC Averaged Latency	Indicates the RPC latency, in ms, averaged for all operations in the last 1,024 packets. For information about how clients are affected when overall server RPC averaged latencies increase, see Understanding Client Throttling Policies.	Shouldn't be higher than 10 ms on average.	To determine if certain protocols are causing overall RPC latencies, monitor MSExchangeIS Client (*)\RPC Average Latency to separate latencies based on client protocol.
MSExchangeIS Client (*)\RPC Average Latency	Shows a server RPC latency, in ms, averaged for the past 1,024 packets for a particular client protocol.	Should be less than 50 ms on average for each client.	Wide disparities between different client types, such as IMAP4, Microsoft Outlook Anywhere, or other clients (MAPI), can help direct troubleshooting to appropriate subcomponents.

RPC Client Throttling Counters

The following table shows RPC client throttling counters.

Counter	Description	Threshold	Troubleshooting
MSExchangeIS Client (*)\RPC Average Latency	RPC Average Latency is a server RPC latency, in ms, averaged for the past 1,024 packets.	Should be less than 50 ms on average for each client.	Wide disparities between different client types, such as IMAP4, Microsoft Outlook Anywhere, or other clients (MAPI), can help direct troubleshooting to appropriate subcomponents.
MSExchangeIS\Client: RPCs Failed/sec	Shows the client-reported rate of failed RPCs (since the store was started).	Should be 0 at all times.	Higher values may indicate RPC threads are exhausted or client throttling is occurring for clients running versions of Outlook earlier than Office Outlook 2007.
MSExchangeIS\Client: RPCs Failed/sec	The client-reported number of failed RPCs (since the store was started).	Should be 0 at all times.

Message Queuing Counters

The following table shows message queuing counters.

Counter	Description	Threshold	Troubleshooting
MSExchangeIS Mailbox(_Total)\Messages Queued for Submission	Shows the current number of submitted messages not yet processed by the transport layer.	Should be below 50 at all times. Shouldn't be sustained for more than 15 minutes.	This may indicate connectivity issues to the transport server.
MSExchangeIS Public(_Total)\Messages Queued for Submission	Shows the current number of submitted messages not yet processed by the transport layer.	Should be less than 20 at all times.

Database Counters

The following table shows database counters.

Counter	Description	Threshold	Troubleshooting
MSExchange Database ==> Instances(*)\Log Generation Checkpoint Depth	Represents the amount of work in the log file count that needs to be redone or undone to the database files if the process fails.	Should be below 500 at all times for the Mailbox server role. A healthy server should indicate between 20 and 30 for each database instance.	If checkpoint depth increases continually for a sustained period, this indicates either a long-running transaction, (which will impact the version store), or a bottleneck involving the database disks.
MSExchange Database(Information Store)\Database Page Fault Stalls/sec	Shows the rate that database file page requests require of the database cache manager to allocate a new page from the database cache.	If this value is nonzero, this indicates that the database isn't able to flush dirty pages to the database file fast enough to make pages free for new page allocations.
MSExchange Database(Information Store)\Log Record Stalls/sec	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.	The average value should be below 10 per second. Spikes (maximum values) shouldn't be higher than 100 per second.	If I/O log write latencies are high, check for RAID5 or synchronize replication on log devices. 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 will assist you in determining which drive(s) to focus on. This counter is an extended Exchange counter in Performance Monitor.
MSExchange Database(Information Store)\Log Threads Waiting	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.	Should be less than 10 on average.	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.
MSExchange Database(Information Store)\Version buckets allocated	Shows the total number of version buckets allocated.	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.
MSExchange Database ==> Instances(*)\I/O Database Reads Average Latency	Shows the average length of time, in ms, per database read operation.	Should be 20 ms on average. Should show 50 ms spikes.
MSExchange Database ==> Instances(*)\I/O Database Writes Average Latency	Shows the average length of time, in ms, per database write operation.	Should be 50 ms on average.	Spikes of up to 100 ms are acceptable if not accompanied by database page fault stalls.
MSExchange Database(Information Store)\Database Cache Size (MB)	Shows the amount of system memory, in megabytes (MB), used by the database cache manager to hold commonly used information from the database files to prevent file operations.	Maximum value is RAM-2GB (RAM-3GB for servers with sync replication enabled). 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. If 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), adding more memory to the system may increase performance. If there is ample memory on the system and the database cache size isn't growing beyond a certain point, the database cache size may be capped at an artificially low limit. Increasing this limit may increase performance.
MSExchange Database(Information Store)\Database Cache % Hit	Shows the percentage of database file page requests fulfilled by the database cache without causing a file operation. If this percentage is too low, the database cache size may be too small.	Should be over 90% for companies with majority online mode clients. Should be over 99% for companies with majority cached mode clients.	If the hit ratio is less than these numbers, the database cache may be insufficient.
MSExchange Database\Log Bytes Write/sec	Shows the rate of bytes written to the log.	Should be less than 10,000,000 at all times.	With each log file being 1,000,000 bytes in size, 10,000,000 bytes/sec would yield 10 logs per second. This may indicate a large message being sent or a looping message.

Client-Related Search Counters

The following table shows client-related search counters.

Counter	Description	Threshold	Troubleshooting
MSExchangeIS Mailbox(*)\Slow Findrow Rate	Shows the rate at which the slower FindRow needs to be used in the mailbox store.	Should be no more than 10 for any specific mailbox store.	Higher values indicate applications are crawling or searching mailboxes, which is affecting server performance. These include desktop search engines, customer relationship management (CRM), or other third-party applications.
MSExchangeIS Mailbox(*)\Search Task Rate	Shows the number of search tasks created per second.	Should be less than 10 at all times.
MSExchangeIS\Slow QP Threads	Shows the number of query processor threads currently running queries that aren't optimized.	Should be less than 10 at all times.
MSExchangeIS\Slow Search Threads	Shows the number of search threads currently running queries that aren't optimized.	Should be less than 10 at all times.

Content Indexing Counters

The following table shows content indexing counters.

Counter	Description	Threshold	Troubleshooting
Process(Microsoft.Exchange.Search.ExSearch)\% Processor time	Shows the amount of processor time currently being consumed by the Exchange Search service.	Should be less than 1% of overall CPU typically and not sustained above 5%. Should be less than 10% of what the store process is during steady state.
Process(msftesq)\%Processor Time	Shows the amount of processor time being consumed to update content indexing within the store process.	Full crawls increase overall processing time, but should never exceed overall store CPU capacity.	Check throttling counters to determine if throttling is occurring due to server performance bottlenecks.
MSExchange Search Indices(*)\Average Latency of RPCs Used to Obtain Content	Shows the average latency, in ms, of the most recent RPCs to the Information Store service. These RPCs are used to get content for the filter daemon for the specified database.	Should coincide with the latencies that Outlook clients are experiencing.
MSExchange Search Indices(*)\ Average Document Indexing Time	Shows the average, in ms, of how long it takes to index documents.	Should be less than 30 seconds at all time.
MSExchange Search Indices(*)\Full Crawl Mode Status	This counter is used to determine if a full crawl is occurring for any specified database.	Indicates whether this .mdb file is going through a full crawl (value=1) or not (value=0).	If CPU resources are high, it's possible content indexing is occurring for a database or set of databases.

Mailbox Assistant Counters

The following table shows mailbox assistant counters.

Counter	Description	Threshold
Process(MSExchangeMailboxAssistants)\%Processor Time	Shows the amount of processor time being consumed by mailbox assistants.	Should be less than 5% of overall CPU capacity.
MSExchange Assistants – Per Assistant (*)\Events in queue	Shows the number of events in the in-memory queue waiting to be processed by the assistants.	Should be a low value at all times. High values may indicate a performance bottleneck.
MSExchange Assistants – Per Database(*)\Events in queue	Shows the number of events in the in-memory queue waiting to be processed by the assistants.	Should be a low value at all times. High values may indicate a performance bottleneck.
MSExchange Assistants – Per Assistant(*)\Average Event Processing Time in Seconds	Shows the average processing time of the events chosen.	Should be less than 2 at all times.
MSExchange Assistants – Per Database(*)\Average Event Processing Time in Seconds	Shows the average processing time of the events chosen.	Should be less than 2 at all times.

Resource Booking Counters

The following table shows resource booking counters.

Counter	Description	Threshold
MSExchange Resource Booking\Average ResourceBooking Processing Time	Shows the average time to process an event in the Resource Booking Attendant.	Should be a low value at all times. High values may indicate a performance bottleneck.
MSExchange Resource Booking\Requests Failed	Shows the total number of failures that occurred while the Resource Booking Attendant was processing events.	Should be 0 at all times.

Calendar Attendant Counters

The following table shows Calendar Attendant counters.

Counter	Description	Threshold
MSExchange Calendar Attendant\Average Calendar Attendant Processing time	Shows the average time to process an event in the Calendar Attendant.	Should be a low value at all times. High values may indicate a performance bottleneck.
MSExchange Calendar Attendant\Requests Failed	Shows the total number of failures that occurred while the Calendar Attendant was processing events.	Should be 0 at all times.

Store Client Request Counters

The following table shows store client request counters.

Counter	Description	Threshold
MSExchange Store Interface(_Total)\RPC Latency average (msec)	Shows the average latency, in ms, of RPC requests. The average is calculated over all RPCs since exrpc32 was loaded.	Should be less than 100 ms at all times.
MSExchange Store Interface(*)\ROP Requests outstanding	Shows the total number of outstanding remote operations requests. Used for determining current load.
MSExchange Store Interface(_Total)\RPC Requests outstanding	Shows the current number of outstanding RPC requests. Used for determining current load.
MSExchange Store Interface(*)\RPC Requests Outstanding	Shows the total number of outstanding RPC requests. Used for determining current load.
MSExchange Store Interface(*)\RPC Requests Sent/sec	Shows the current rate of initiated RPC requests per second. Used for determining current load.	Not applicable.
MSExchange Store Interface(*)\RPC Slow Requests latency average (msec)	Shows the average latency, in ms, of slow requests. Used for determining the average latencies of RPC slow requests.
MSExchange Store Interface(*)\RPC Requests failed (%)	Shows the percentage of failed requests in the total number of RPC requests. Failed means the sum of failed with error code plus failed with exception.	Should be less than 1 at all times.
MSExchange Store Interface(*)\RPC Slow Requests (%)	Shows the percentage of slow RPC requests among all RPC requests. A slow RPC request is one that has taken more than 500 ms.	Should be less than 1 at all times.
MSExchange Mail Submission(*)\Successful Submissions Per Second	Determines current mail submission rate.	Not applicable.
MSExchange Mail Submission(*)\Hub Servers In Retry	Shows the number of Hub Transport servers in retry mode.	Should be 0 at all times.
MSExchange Mail Submission(*)\Failed Submissions Per Second	Shows the number of failed submissions per second.	Should be 0 at all times.
MSExchange Mail Submission(*)\Temporary Submission Failures/sec	Shows the number of temporary submission failures per second.	Should be 0 at all times.
MSExchange Replication(*)\CopyQueueLength	Shows the number of transaction log files waiting to be copied to the passive copy log file folder. A copy isn't considered complete until it has been checked for corruption.	Should be less than 1 at all times for continuous replication.
MSExchange Replication(*)\ReplayQueueLength	Shows the number of transaction log files waiting to be replayed into the passive copy.	Indicates the current replay queue length. Higher values cause longer store mount times when a handoff, failover, or activation is performed.
MSExchange Replica Seeder(*)\Database Seeding Progress %	Shows the finished percentage of seeding. Its value is from 0 through 100%. Used to determine if seeding is occurring for a particular database, which is possibly affecting overall server performance or current network bandwidth.	Not applicable.
MSExchangeIS\RPC Operations/sec	Indicates the current number of RPC operations occurring per second.	Should closely correspond to historical baselines. Values much higher than expected indicate that the workload has changed, while values much lower than expected indicate a bottleneck preventing client requests from reaching the server.

Client Activity Counters

The following table shows client activity counters.

Counter	Description	Threshold
MSExchangeIS\RPC Client Backoff/sec	Indicates the rate at which client backoffs are occurring. Higher values may indicate that the server may be incurring a higher load resulting in an increase in overall averaged RPC latencies, causing client throttling to occur. This can also occur when certain client user actions are being performed. Depending on what the client is doing and the rate at which RPC operations are occurring, it may be normal to see backoffs occurring.	Not applicable.
MSExchangeIS\Client: RPCs Failed/sec	Shows the client-reported rate of failed RPCs (since the store was started).	Should be 0 at all times. Higher values may indicate RPC threads are exhausted or client throttling is occurring for clients running versions of Outlook earlier than Outlook 2007.

Information Store Counters

The following table shows information store counters for determining user load.

Counter	Description	Threshold
MSExchangeIS Client(*)\RPC Operations/sec	Shows what client protocol is performing an excessive amount of RPC Operations/sec. High IMAP4, POP3, or Outlook Anywhere latency can indicate problems with Client Access servers rather than Mailbox servers. This is especially true when other clients (which includes MAPI) latency is lower in comparison. In some instances, high IMAP latencies could indicate a bottleneck on the Mailbox server in addition to the latencies that the Client Access server is experiencing.	Not applicable.
MSExchangeIS Client (*)\RPC Average Latency	RPC Average Latency is a server RPC latency, in ms, averaged for the past 1,024 packets.	Should be less than 50 ms on average.
MSExchangeIS Client(*)\JET Log Records/sec	Shows the rate that database log records are generated while processing requests for the client. Used to determine current load.	Not applicable.
MSExchangeIS Client(*)\JET Pages Read/sec	Shows the rate that database pages are read from disk while processing requests for the client. Used to determine current load.	Not applicable.
MSExchangeIS Client(*)\Directory Access: LDAP Reads/sec	Shows the current rate that LDAP reads occur while processing requests for the client. Used to determine the current LDAP read rate per protocol.	Not applicable.
MSExchangeIS Client(*)\Directory Access: LDAP Searches/sec	Shows the current rate that LDAP searches occur while processing requests for the client. Used to determine the current LDAP search rate per protocol.	Not applicable.
MSExchangeIS Mailbox(_Total)\Messages Delivered/sec	Shows the rate that messages are delivered to all recipients. Indicates current message delivery rate to the store.	Not applicable.
MSExchangeIS Mailbox(_Total)\Messages Sent/sec	Shows the rate that messages are sent to transport. Used to determine current messages sent to transport.	Not applicable.
MSExchangeIS Mailbox(_Total)\Messages Submitted/sec	Shows the rate that messages are submitted by clients. Used to determine current rate that messages are being submitted by clients.	Not applicable.
MSExchangeIS\User Count	Shows the number of users connected to the information store. Used to determine current user load.	Not applicable.
MSExchangeIS Public(_Total)\Replication Receive Queue Size	Shows the number of replication messages waiting to be processed.	Should be less than 100 at all times. This value should return to a minimum value between replication intervals.

Mailbox Assistant Counters

The following table shows mailbox assistant counters.

Counter	Description	Threshold
MSExchange Assistants – Per Database(*)\Mailboxes Processed/sec	Shows the rate of mailboxes processed by time-based assistants per second. Determines current load statistics for this counter.	Not applicable.
MSExchange Assistants – Per Database(*)\Events Polled/sec	Shows the number of events polled per second. Determines current load statistics for this counter.	Not applicable.

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