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

Topic Last Modified: 2012-07-23

This topic provides information about counters relevant to the Client Access 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.

Outlook Web App Counter

The following table shows a Microsoft Office Outlook Web App counter.

Counter Description Threshold

MSExchange OWA\Average Search Time

Shows the average time that elapsed while waiting for a search to complete.

Should be less than 5,000 milliseconds (ms) at all times.

ASP.NET Counters

The following table shows ASP.NET counters.

Counter Description Threshold Troubleshooting

ASP.NET\Application Restarts

Shows the number of times the application has been restarted during the Web server's lifetime.

Should be 0 at all times.

ASP.NET\Worker Process Restarts

Shows the number of times a worker process has restarted on the computer.

Should be 0 at all times.

ASP.NET\Request Wait Time

Shows the number of ms the most recent request was waiting in the queue.

Should be 0 at all times.

Values greater than 0 should be investigated.

ASP.NET Applications(*)\Requests In Application Queue

Shows the number of requests in the application request queue.

Should be 0 at all times.

Values greater than 0 should be investigated.

Availability Service Counter

The following table shows an availability service counter.

Counter Description Threshold

MSExchange Availability Service\Average Time to Process a Free Busy Request

Shows the average time to process a free/busy request in seconds. One request may contain multiple mailboxes. Free/busy responses don't have meeting suggestions.

Should always be less than 5.

ActiveSync Service Counters

The following table shows ActiveSync service counters.

Counter Description Threshold

MSExchange ActiveSync\Ping Commands Pending

Shows the number of ping commands currently pending on the server.

Ping Commands Pending and Sync Commands Pending are the number of hanging requests, which should be almost equal to the number of Direct Push and hanging sync users.

MSExchange ActiveSync\Sync Commands Pending

Shows the number of sync commands currently pending on the server.

Ping Commands Pending and Sync Commands Pending are the number of hanging requests, which should be almost equal to the number of Direct Push and hanging sync users.

MSExchange ActiveSync\Current Requests

Shows the number of HTTP requests waiting to be assigned to a thread.

Average of 50–100.

RPC/HTTP Proxy Counters (Windows Server 2008 Only)

The following table shows Windows Server 2008 RPC/HTTP proxy counters.

Counter Description Threshold

RPC/HTTP Proxy\Number of Failed Back-End Connection attempts per Second

Shows the rate at which the RPC proxy attempts are occurring but failing to establish a connection to a back-end server.

Should be 0 at all times.

RPC/HTTP Proxy\Current Number of Incoming RPC over HTTP Connections

Shows the current number of front-end HTTP connections. Determines current user load.

Not applicable.

RPC/HTTP Proxy\Current Number of Unique Users

Shows the number of unique users currently connected to a back-end server via RPC/HTTP. Determines current user load.

Not applicable.

RPC/HTTP Proxy\RPC/HTTP Requests per Second

Shows the rate of RPC/HTTP requests sent to the back-end servers. Determines current Microsoft Outlook Anywhere load.

Not applicable.

RPC Client Access Counters

The following table shows RPC Client Access counters.

Counter Description Threshold

MSExchange RpcClientAccess\RPC Averaged Latency

Shows the latency, in ms, averaged for the past 1,024 packets.

Should be below 250 ms.

MSExchange RpcClientAccess\RPC Operations/sec

Shows the rate at which RPC operations occur, per second.

MSExchange RpcClientAccess\RPC Requests

Shows the number of client requests currently being processed by the RPC Client Access service.

Shouldn't be over 40.

Address Book Service Counters

The following table shows Exchange 2010 address book service counters.

Counter Description Threshold

MSExchangeAB\NSPI RPC Browse Requests Average Latency

Shows the average time, in ms, that Name Service Provider Interface (NSPI) browse requests took to complete during the sampling period.

Should be below 1,000 ms.

MSExchangeAB\NSPI RPC Requests Average Latency

Shows the average time, in ms, that NSPI requests took to complete during the sampling period.

Should be below 1,000 ms.

MSExchangeAB\Referral RPC Requests Average Latency

Shows the average time, in ms, that referral requests took to complete during the sampling period.

Should be below 1,000 ms.

Control Panel Counters

The following table shows Exchange 2010 Control Panel counters.

Counter Description Threshold

MSExchange Control Panel\Outbound Proxy Requests - Average Response Time

Shows the average time (in ms) that requests sent to a secondary Client Access server took to complete during the sampling period.

The average should be under 6,000 ms.

MSExchange Control Panel\Requests - Average Response Time

Shows the average time (in ms) the Exchange Control Panel took to respond to a request during the sampling period.

The average should be under 6,000 ms.

Client Access Server OAB Download Counters

The following table shows Client Access server offline address book (OAB) download counters.

Counter Description Threshold Troubleshooting

MSExchangeFDS:OAB(*)\Download Task Queued

Shows the number of OAB download tasks queued since the File Distribution service started.

Should be 0 at all times.

Values greater than 0 indicate a failure to copy OAB data files from Mailbox servers.

MSExchangeFDS:OAB(*)\Download Tasks Completed

Shows the number of OAB download tasks completed since the File Distribution service started. The default value is every 480 minutes or 8 hours.

Should be less than or equal to 3 per day.

Values greater than 3 per day indicate the schedule for the Client Access server to download updated OAB files isn't a default schedule.

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.

Client Access Server Counters

The following table shows some common Client Access server counters for determining load on your servers.

Counter Description Threshold

MSExchange ActiveSync\Requests/sec

Shows the number of HTTP requests received from the client via ASP.NET per second. Determines the current Exchange ActiveSync request rate.

Not applicable.

MSExchange ActiveSync\Ping Commands Pending

Shows the number of ping commands currently pending in the queue.

Not applicable.

MSExchange ActiveSync\Requests/sec

Shows the number of HTTP requests received from the client via ASP.NET per second. Used only to determine current user load.

Not applicable.

MSExchange ActiveSync\Sync Commands/sec

Shows the number of sync commands processed per second. Clients use this command to synchronize items within a folder.

Not applicable.

MSExchange Availability Service\Availability Requests (sec)

Shows the number of requests serviced per second. The request can be only for free/ busy information or include suggestions. One request may contain multiple mailboxes. Determines the rate at which Availability service requests are occurring.

Not applicable.

MSExchange OWA\Current Unique Users

Shows the number of unique users currently logged on to Outlook Web App. This value monitors the number of unique active user sessions, so that users are only removed from this counter after they log off or their session times out. Determines current user load.

Not applicable.

MSExchange OWA\Requests/sec

Shows the number of requests handled by Outlook Web App per second. Determines current user load.

Not applicable.

MSExchangeAutodiscover\Requests/sec

Shows the number of Autodiscover service requests processed each second. Determines current user load.

Not applicable.

MSExchangeWS\Requests/sec

Shows the number of requests processed each second. Determines current user load.

Not applicable.

Web Service(_Total)\Current Connections

Shows the current number of connections established with the Web service. Determines current user load.

Not applicable.

WebService(_Total)\Connection Attempts/sec

Shows the rate that connections to the Web service are being attempted. Determines current user load.

Not applicable.

Web Service(_Total)\ISAPI Extension Requests/sec

Shows the rate that Internet Server API (ISAPI) extension requests are received by the Web service. Determines current user load. Outlook Anywhere clients make use of this ISAPI extension for RPC over HTTP requests on servers running Windows Server 2003. For Windows Server 2008 counters, see "RPC/HTTP Proxy Counters (Windows Server 2008 Only)" earlier in this topic.

Not applicable.

Web Service(_Total)\Other Request Methods/sec

Shows the rate HTTP requests are made that don't use the OPTIONS, GET, HEAD, POST, PUT, DELETE, TRACE, MOVE, COPY, MKCOL, PROPFIND, PROPPATCH, SEARCH, LOCK, or UNLOCK methods. Determines current user load.

Not applicable.

Exchange Control Panel Load Counters

The following table shows Exchange 2010 Control Panel load counters.

Counter Description Threshold

MSExchange Control Panel\ASP.Net Request Failures/sec

Shows the number of failures per second detected by ASP.NET in the Exchange Control Panel.

Not applicable.

MSExchange Control Panel\Explicit Sign-On Inbound Proxy Requests/sec

Shows the number of explicit sign-on requests received from a primary Client Access server per second.

Not applicable.

MSExchange Control Panel\Explicit Sign-On Inbound Proxy Sessions/sec

Shows the number of explicit sign-on inbound proxy sessions loaded per second in the Exchange Control Panel.

Not applicable.

MSExchange Control Panel\Explicit Sign-On Outbound Proxy Requests/sec

Shows the number of explicit sign-on requests sent to a secondary Client Access server per second.

Not applicable.

MSExchange Control Panel\Explicit Sign-On Outbound Session Requests/sec

Shows the number of explicit sign-on outbound proxy sessions loaded per second in the Exchange Control Panel.

Not applicable.

MSExchange Control Panel\Explicit Sign-On Standard RBAC Requests/sec

Shows the number of requests received per second by an explicit sign-on standard RBAC session.

Not applicable.

MSExchange Control Panel\Explicit Sign-On Standard RBAC Sessions/sec

Shows the number of explicit sign-on standard RBAC sessions loaded per second in the Exchange Control Panel.

Not applicable.

MSExchange Control Panel\Inbound Proxy Requests/sec

Shows the number of requests received from a primary Client Access server per second.

Not applicable.

MSExchange Control Panel\Inbound Proxy Sessions/sec

Shows the number of inbound proxy sessions loaded per second in the Exchange Control Panel.

Not applicable.

MSExchange Control Panel\Outbound Proxy Requests - Average Response Time

Shows the average time (in ms) that requests sent to a secondary Client Access server took to complete during the sampling period.

Should be under 6,000 ms.

MSExchange Control Panel\Outbound Proxy Requests/sec

Shows the number of requests sent to a secondary Client Access server per second.

Not applicable.

MSExchange Control Panel\Outbound Proxy Sessions/sec

Shows the number of outbound proxy sessions loaded per second in the Exchange Control Panel.

Not applicable.

MSExchange Control Panel\PowerShell Runspaces - Activations/sec

Shows the number of Windows PowerShell runspaces activated per second in the Exchange Control Panel.

Not applicable.

MSExchange Control Panel\PowerShell Runspaces - Average Active Time

Shows the average time (in seconds) that a Windows PowerShell runspace stays active while executing cmdlets in the Exchange Control Panel during the sampling period.

Not applicable.

MSExchange Control Panel\PowerShell Runspaces/sec

Shows the number of Windows PowerShell runspaces created per second in the Exchange Control Panel.

MSExchange Control Panel\RBAC Sessions/sec

Shows the number of RBAC sessions loaded per second in the Exchange Control Panel.

Not applicable.

MSExchange Control Panel\Requests - Activations/sec

Shows the number of requests activated per second in the Exchange Control Panel.

Not applicable.

MSExchange Control Panel\Requests - Average Response Time

Shows the average time (in ms) the Exchange Control Panel took to respond to a request during the sampling period.

Should be under 6,000 ms.

Availability Service Load Counter

The following table shows an availability service load counter.

Counter Description Threshold

MSExchange Availability Service\Availability Requests (sec)

Shows the number of requests serviced per second. The request can be only for free/busy information or include suggestions. One request may contain multiple mailboxes. Determines the rate at which Availability service requests are occurring.

Not applicable.

RPC Client Access Load Counters

The following table shows RPC Client Access load counters.

Counter Description Threshold

MSExchange RpcClientAccess\Active User Count

Shows the number of unique users that have shown some activity in the last 2 minutes.

Not applicable.

MSExchange RpcClientAccess\Connection Count

Shows the total number of client connections maintained.

Not applicable.

MSExchange RpcClientAccess\RPC Operations/sec

Shows the rate at which RPC operations occur, per second.

Not applicable.

MSExchange RpcClientAccess\User Count

Shows the number of users connected to the service.

Not applicable.

Exchange Address Book Load Counters

The following table shows Exchange Address Book load counters.

Counter Description Threshold

MSExchangeAB\NSPI Connections Current

Shows the number of NSPI clients currently connected to the server.

Not applicable.

MSExchangeAB\NSPI Connections/sec

Shows the number of NSPI client connections established to the server each second.

Not applicable.

MSExchangeAB\NSPI RPC Requests/sec

Shows the rate at which NSPI requests occur each second.

Not applicable.

MSExchangeAB\Referral RPC Requests/sec

Shows the rate at which referral requests occur each second.

Not applicable.