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The general findings from the analysis of the Microsoft internal deployment are described by client access method and protocol later in this topic. A select group of Client Access servers was used to analyze performance. The specifications of the selected Client Access servers that were used for the tests described in this topic are detailed in the following table. Table 40 Client Access server specifications

Model CPU

information

CPU count and core per CPU

Core count Memory Network

HP ProLiant DL385 G1 AMD Opteron Model 275; 2.2 gigahertz (GHz), 1 megabyte (MB) L2 dual- core 2 and 2 4 4 GB HP NC7782 Gigabit Server Adapter

Specific performance objects, counters, and instances were collected during peak load and other observation times. In addition to the specific counters listed in tables in the following sections, processor, memory, network, and disk performance counters were also collected and factored into the overall analysis. For more information, see "Recommended

Performance Counters" later in this topic.

The following table shows the peak loads that were observed, measured in terms of requests per second and number of concurrent users, and the number of users that each Client Access server is sized to support.

Table 41 Peak load and user count summary

Services used Load at peak Supported users per Client Access server

Outlook Web Access only 70 requests per second 4,500 concurrent users

Services used Load at peak Supported users per Client Access server

Multiple services:

• 25%

Exchange ActiveSync

• 5% Outlook Web Access

• 70% Outlook Anywhere

Exchange ActiveSync:

• 5 requests per second

• 500 concurrent users Outlook Web Access:

• 20 requests per second

• 100 concurrent users Outlook Anywhere:

• 40 requests per second

• 1,400 concurrent users

Exchange ActiveSync: 500 Outlook Web Access: 2,140 Outlook Anywhere: 1,980

Note:

All scenarios include an additional load resulting from the use of Exchange Web Services, as well as the use of the Availability service by clients. In the multiple services scenario, four Exchange Web Services or Availability service requests per second were observed. This load includes Outlook clients on the internal network.

Outlook Anywhere

A select group of Client Access servers was used to analyze Outlook Anywhere performance. Microsoft measured the total number of Web connections on each server to determine peak loads, as well as the number of connection attempts per second (sec). The performance object, counter, and instance used to measure these values are listed in the following table. Table 42 Values to use when measuring Outlook Anywhere connections

Object Counter Instance Description

Web service Current Connections _Total The current number of connections established with the Web service. Web service Connection

Attempts/sec

_Total The rate at which

connections to the Web service are being attempted.

The following table provides details about the collected values for the preceding load- indicating performance counters for three of the Client Access servers used to analyze Outlook Anywhere performance.

Table 43 Unique Outlook Anywhere users per server during a peak one-hour period

Server Unique users Connection attempts

per second

Current connections

CAS1 3,978 43.7 24,443

CAS2 2,988 36.1 21,823

CAS3 4,065 35.2 22,083

After analyzing the collected data, it was found that processor utilization was not significantly affected by user load for Outlook Anywhere. Overall processor utilization was stable at approximately 24 percent at peak load. Lsass.exe and the worker process (W3wp.exe) hosting the service were the primary processor load generators and showed good correlation with total CPU utilization. Lsass.exe and W3wp.exe also showed the highest memory load, with Lsass.exe showing significantly higher memory usage than any other process. No indications of network bottlenecks were detected, and no significant disk activity beyond logging and paging was observed.

Outlook Web Access

A select group of Client Access servers was used to analyze Outlook Web Access performance. On the test servers, 90 percent of the users ran the Premium version of Outlook Web Access, and 10 percent of the users ran the Light version. Web browser distribution was not examined, but that is not expected to significantly affect usage patterns beyond determining which clients can make use of the Premium version. The following table details the values of the load-indicating performance counters under the MSExchange OWA

Table 44 Performance data collected for Outlook Web Access performance object that were measured on the Client Access servers.

Performance counter Average value

Average Response Time 133 milliseconds (ms)

Logons/sec .597

Request/sec 26.9

Average Search time 275 ms

After analyzing the collected data, it was found that CPU utilization averaged 24.168 percent, with a maximum spike of 44.7 percent, indicating no CPU bottlenecks. On a per-process basis, the W3wp.exe process hosting the services was the primary load generator, averaging 70.7 percent CPU utilization. Occasional spikes were seen in the transcoding service and other peripherally related processes. However, these increases were limited in duration, and did not appear to significantly affect the server. An average of 10.7 pages per second was measured, with an average of 842.7 page faults per second. This indicates some paging activity to disk. However, this is well within normal operational parameters and does not indicate abnormal memory pressure. As expected, the W3wp.exe process hosting the server had the highest memory working set. No indications of any network or disk bottlenecks were found, and overall, no indication of any disk I/O activity beyond normal operations was observed. Finally, it was determined that a single Client Access server was capable of supporting the entire user load.

Exchange ActiveSync

A select group of Client Access servers was used to analyze Exchange ActiveSync performance. The following table details the values of the load-indicating performance counters under the MSExchange ActiveSync performance object that were measured on the Client Access servers.

Note:

The Average Request Time counter also includes Ping Request Time, which significantly increases Average Request Time values. As a result, the Average Request Time counter is not a good indicator of general response times. Table 45 Performance data collected for Exchange ActiveSync

Performance counter Value

Average Request Time 104.7 sec

Ping Commands Pending 2031.9

Requests/sec 18.8

Sync Commands/sec 7.5

After analyzing the collected data, it was found that the peak load was 2,129 concurrent users averaging 18.8 requests per second. During peak loads, the Client Access servers averaged 36.1 percent CPU utilization, and had a peak value of 68.8 percent, indicating no significant CPU bottlenecks. The W3wp.exe process hosting the service was the primary load generator. An average of 110 pages per second was measured with an average of 730.3 page faults per second. This indicates some paging activity was occurring. However, this is well within normal operational parameters and does not indicate abnormal memory pressure. As expected, the W3wp.exe process hosting the service had the highest memory working

set. No indications of any network or disk bottlenecks were found, and overall, no indication of any disk I/O activity beyond normal operations was observed.

Exchange Web Services

A select group of Client Access servers was used to analyze Exchange Web Services performance. The following table details the values of the load-indicating performance counters under the MSExchangeWS and MSExchange Availability Service performance objects that were measured on the Client Access servers.

Note:

Because Exchange Web Services requests come from two sources, Outlook 2007 and the internal, automated processes that use Web service APIs, and because the Outlook 2007 Web service load on the server is a function of the amount of

calendaring requests being made, no attempt was made to isolate the load in terms of number of users. Most requests from Outlook 2007 come in the form of availability requests. Because there are few ways to distinguish the load difference between these requests, the Exchange Web Services are examined as a whole, and only limited attempts were made to quantify the load as a direct result of availability requests. Finally, it should be noted that any availability request that exceeds 25 seconds is considered a failure. In all cases, the value of the Average Response Time counter of the MSExchange Availability Service

Table 46 Performance data collected for Exchange Web Services

object must be significantly lower than 25 seconds, and any transient peaks exceeding 25 seconds should be examined as a performance bottleneck.

Performance object and counter Value

MSExchangeWS - Requests/sec 0.2

MSExchangeWS - Average Response Time 0.9 MSExchange Availability Service - Average Time to Process a Free Busy Request

0.2

MSExchange Availability Service - Availability Requests (sec)

2.5

After analyzing the collected data, it was found that during peak loads, the Client Access servers averaged 10.7 percent total CPU utilization, with a peak value of 31.7 percent, indicating no significant CPU bottlenecks. The W3wp.exe process hosting the service was the major load generator. An average of 19.9 pages per second was measured with an average of 414.7 page faults per second. This indicates some paging activity was occurring. However, this is well within normal operational parameters and does not indicate abnormal memory pressure. As a result of the light load applied to the Web service, the working set of

the W3wp.exe process hosting the service was not the largest value observed. However, because the memory pressure on the computer was light, it is assumed that this is a valid representational value. No indications of any network or disk bottlenecks were found, and overall, no indication of any disk I/O activity beyond normal operations was observed.