Estimate performance and capacity requirements for InfoPath Forms Services in SharePoint Server 2010

 

Applies to: InfoPath Forms Services

This article provides guidance on the effects of using InfoPath Forms Services in Microsoft SharePoint Server 2010 on topologies running Microsoft SharePoint Server 2010.

The tests described in this article were designed to help develop estimates of how different farm configurations respond to changes to the following variables:

• Front-end Web server scale out for different submit operations

• Front-end Web server scale out for different InfoPath list operations

• Impact of form complexity on throughput

For general information about capacity planning for SharePoint Server 2010, see Performance and capacity management (SharePoint Server 2010).

In this article:

• Test farm characteristics

• Test results

• Recommendations

Test farm characteristics

The specific capacity and performance figures presented in this article will differ from the figures in real-world environments. The figures presented are intended to provide a starting point for the design of an appropriately scaled environment. After you have completed your initial system design, test the configuration to determine whether your system will support the factors in your environment.

Hardware, settings, and topology

This section describes the hardware and topology used to complete these tests, as well as the test scenarios in the following sections:

• Lab hardware

• Topology

• Test scenarios

Lab hardware

To provide a high level of test-result detail, several farm configurations were used for testing. Farm configurations ranged from one to six Web servers and a single database server that is running Microsoft SQL Server 2008 database software. Load testing was performed with Visual Studio Team System 2008. The tests also included two agent computers. All computers were 64-bit.

The following table lists the specific hardware that was used for testing.

	Web server	Database server	Agent 1 and Agent 2
Role	Front-end Web server	SQL Server	Agent
Processors	2x Xeon L5420 @ 2.5 GHz (8 cores)	4x Xeon E7330 @ 2.4 GHz (16 cores)	2x Xeon L5420 @ 2.5 GHz (8 cores)
RAM	16 GB	32 GB	16 GB
Operating system	Windows Server 2008 R2	Windows Server 2008 R2	Windows Server 2008 R2
Storage: operating system	4x 146 GB, 10K RPM, RAID 0	2x 146 GB, 15K RPM, RAID 1	4x 146 GB, 10K RPM, RAID 0
Storage: backups		3x 300 GB, 15K RPM, RAID 5
Storage: SQL Server Data		9x 300 GB, 15K RPM, RAID 5
Storage: SQL Server Log		6x 300 GB, 15K RPM, RAID 5
Number of network adapters	1	4	1
Network adapter speed	1 Gb per second	1 Gb per second	1 Gb per second
Authentication	NTLM	NTLM	NTLM
Software version	SharePoint Server 2010 (Pre-Release Version)	SQL Server 2008 SP1 CU6
Number of SQL Server instances		1
Load balancer type	Windows Network Load Balancing	Windows Network Load Balancing	N/A
Information Rights Management (IRM) settings	Off	Off
Anti-virus settings	Not installed	Not installed	Not installed

Topology

InfoPath capacity planning topology

Test scenarios

This section defines the test scenarios and provides an overview of the test process that was used for each scenario. Test results are given in later sections in this article.

Form templates

Testing was performed with a form template that consists of text boxes, radio buttons, and drop-down list boxes. This template will be referred to as the baseline solution. The following is a screen shot of the form template for context.

Passport application form

The baseline solution was used to create derivative form templates. These form templates are created by making scoped modification to the baseline solution template and saving it as a new template. This approach enabled us to do comparison of different operations and aspects of form design. The following table describes the different form templates used in testing.

Form template	Number of fields	Type of submit	Number of validation rules	First request optimized	Administrator deployed	Notes
baseline solution	44	None	4	Yes	No
baseline solution with Web service submit	44	Web service	4	Yes	Yes
baseline solution with document library submit	44	SharePoint document library	4	Yes	Yes
Baseline solution without first request optimization	44	Web service	5	No	Yes	The extra validation rule is Date is in the past. Since this rule uses the today() function, the first request requires state data.
Baseline solution with 2x fields	88	Web service	4	Yes	Yes
Baseline solution with 3x fields	132	Web service	4	Yes	Yes
Baseline solution with 4x fields	176	Web service	4	Yes	Yes
Baseline solution with validation	44	Web service	10	No	Yes
Baseline solution with 2x validation	44	Web service	20	No	Yes
Baseline solution with 4x validation	44	Web service	40	No	Yes

InfoPath list form

A modified version of an issue tracking list was used to test the InfoPath list form operations. Two modifications were made to the list. First, the Assigned To column was removed. Second, the Related Issues column was set to not allow multiple values. Finally, the list was prepopulated with 100 items. The following is a screen shot of the list.

List form

Test definitions

Scale-out tests

The following table describes the tests used to for the Web front-end, scale-out tests.

Scenario description	Form template used	Test steps	Number of postbacks
Baseline solution new	Baseline solution	Open a new instance of the baseline solution.	0
Save new baseline solution	Baseline solution	Open a new instance of the baseline solution. Fill out a form and save it to a document library.	1
Baseline solution with document library submit	Baseline solution with document library submit	Open a new instance of the baseline solution with document library submit. Fill out a form and then click Submit. This sends the form data to a SharePoint document library.	1
Baseline solution with Web service submit	Baseline solution with Web service submit	Open a new instance of the baseline solution with Web service submit. Fill out a form and then click Submit. This sends the form data to a Web service.	1
Baseline solution with document library submit x5	5 copies of the baseline solution with Web service submit form template with each one deployed to its own document library	For each document library: Open a new instance of the baseline solution with document library submit. Fill out a form and then click Submit. This sends the form data to a SharePoint document library.	1
Baseline solution open	Baseline solution with document library submit	Open a baseline solution form that has already been completed. The form is opened from a document library.	0

Form complexity tests

The following table describes the tests used for the form complexity tests.

Test name	Form template used	Test steps	Number of postbacks
Baseline solution with 1x controls	Baseline solution with Web service submit	Open a new instance of the baseline solution with Web service submit. Fill out a form and then click Submit. This sends the form data to a Web service.	1
Baseline solution with 2x controls	Baseline solution with 2x controls	Open a new instance of the baseline solution with 2x controls. Fill out a form and then click Submit. This sends the form data to a Web service.	1
Baseline solution with 3x controls	Baseline solution with 3x controls	Open a new instance of the baseline solution with 3x controls. Fill out a form and then click Submit. This sends the form data to a Web service.	1
Baseline solution with 4x controls	Baseline solution with 4x controls	Open a new instance of the baseline solution with 4x controls. Fill out a form and then click Submit. This sends the form data to a Web service.	1
Baseline solution without first request optimization	Baseline solution without first request optimization	Open a new instance of the baseline solution without first request optimization. Fill out a form and then click Submit. This sends the form data to a Web service.	1
Baseline solution with validation	Baseline solution with validation	Open a new instance of the baseline solution with validation. Fill out a form and then click Submit. This sends the form data to a Web service.	1
Baseline solution with 2x validation	Baseline solution with 2x validation	Open a new instance of the baseline solution with 2x validation. Fill out a form and then click Submit. This sends the form data to a Web service.	1
Baseline solution with 4x validation	Baseline solution with 4x validation	Open a new instance of the baseline solution with 4x validation. Fill out a form and then click Submit. This sends the form data to a Web service.	1

InfoPath list form tests

The following table describes the tests used for the InfoPath list form tests.

Test name	Test Step	# of Postbacks
Issue tracking display	Open an existing issue tracking list item in display view.	0
Issue tracking edit	Open an existing issue tracking list item in edit view.	0
Issue tracking new	Open a new item for the issue tracking list.	0

Test results

All the tests reported in this article were conducted without think time, a natural delay between consecutive operations. In a real-world environment, each operation is followed by a delay as the user performs the next step in the task. By contrast, in these tests, each operation was immediately followed by the next operation, which resulted in a continual load on the farm. This load can cause database contention and other factors that can adversely affect performance.

For each topology, a series of three tests was run: calibration, green zone, and maximum throughput. The calibration run uses a step-load pattern. A step-load pattern increases the number of virtual users over time. The results of the calibration run determine the user load for the green zone and maximum throughput tests. The green zone and maximum throughput tests both use constant load pattern for a period of 5 minutes. The requests per second (RPS) reported in this document is the average RPS at the end of the five minute constant load test.

Some of the cells in the results tables have a dash. This indicates that the test was not run for that topology. The test was not run because the results of other runs indicate that there is no expected increase in RPS for that particular topology.

Bottlenecks in InfoPath Forms Services in SharePoint Server 2010 are described in greater detail in Common bottlenecks and their causes, later in this article.

Effect of Web front-end scale-out for different submit operations

The following table shows the green zone test results of scaling out front-end Web servers for various submit operations in SharePoint Server 2010.

	Baseline solution save	Baseline solution with Web service submit	Baseline solution with SharePoint Server 2010 submit	Baseline solution with SharePoint Server 2010 submit using five document libraries
1x1	165	245	160	139
2x1	292	471	301	280
4x1	479	896	478	544
6x1	467	1395	-	599

The following graph shows the green zone throughput for different InfoPath submit operations on different Web front-end topologies. SharePoint Server 2010 submit can scale to four front-end Web servers. However, a farm running five document library submit forms in parallel can achieve more throughput with six front-end Web servers than a single document library can with six front-end Web servers. A farm will generally have more than one InfoPath solution that is deployed. This result means that one of those individual solutions will reach maximum throughput at four front-end Web servers. However, the collective throughput of all the solutions can scale beyond four front-end Web servers. Web service submit has the most throughput and scales to six front-end Web servers.

Green zone throughput for submit operations

The following table shows the Maximum test results of scaling out front-end Web servers for various submit operations in SharePoint Server 2010.

	Baseline solution save	Baseline solution with Web service submit	Baseline solution with SharePoint Server 2010 submit	Baseline solution with SharePoint Server 2010 submit using five document libraries)
1x1	286	470	301	285
2x1	484	912	464	518
4x1	-	1484	478	601
6x1	-	1483	-	-

The following graph shows the maximum throughput for different InfoPath submit operations on different front-end topologies. SharePoint Server 2010 submit and save scale to two front-end Web servers. However, a farm running five document library submit forms in parallel can achieve more throughput with four front-end Web servers than a single document library with four front-end Web servers. A farm will generally have more than one InfoPath solution that is deployed. This result means that one of those individual solutions will reach maximum throughput at four front-end Web servers. However, the collective throughput of all the solutions can scale beyond four front-end Web servers. Web service submit has the most throughput and scales to four front-end Web servers.

Maximum throughput for submit operations

Effect of front-end Web server scale out for InfoPath list operations

The following table shows the green zone test results of adding front-end Web servers for InfoPath list operations in SharePoint Server 2010.

	Issue tracking display	Issue tracking new	Issue tracking edit
1x1	77	67	56
2x1	153	125	106
4x1	295	236	212
6x1	455	431	416

The following graph shows the green zone throughput for InfoPath list operations. All the operations show increasing throughput from adding front-end Web servers. The results also suggest that adding more than six front-end Web servers will continue to increase throughput. This increase was observed outside the capacity planning testing. The display operation has more throughput than the new operation, which has more throughput than the edit operation.

Green zone throughput for list operations

The following table shows the maximum throughput test results of adding front-end Web servers for InfoPath list operations in SharePoint Server 2010.

	Issue tracking display	Issue tracking new	Issue tracking edit
1x1	143	126	100
2x1	263	243	191
4x1	524	457	364
6x1	747	679	521

The following graph shows the maximum throughput for the InfoPath list operations. All the operations show increasing throughput from adding front-end Web servers. The results also suggest that adding more than six front–end Web servers will continue to increase throughput. This increase was observed outside the capacity planning testing. The display operation has more throughput than the new operation, which has more throughput than the edit operation.

Maximum throughput for list operations

Effect of Web front-end scale out for new and open operations

The following table shows the test results of adding front-end Web servers for new and open InfoPath operations in SharePoint Server 2010.

	Issue tracking new	Issue tracking display	Baseline solution new	Baseline solution open
1x1	67	77	197	129
2x1	125	153	379	296
4x1	236	295	802	575
6x1	431	455	1182	869

The following graph shows the green zone throughput for new and open InfoPath operations. All the operations see increasing throughput from adding front-end Web servers. The results suggest that adding more than six front-end Web servers will continue to increase throughput. This increase was observed outside the capacity planning testing. Document library new and open operations have more throughput than InfoPath list new and display operations.

Green zone throughput for new and open operations

	Issue tracking new	Issue tracking display	Baseline solution New	Baseline solution open
1x1	126	143	408	282
2x1	243	263	775	558
4x1	457	524	1285	996
6x1	679	747	1360	1104

The following graph shows the maximum throughput for InfoPath list operations. All the operations show increasing throughput from adding front-end Web servers. The results show that the document library new and open operations scale to six front-end Web servers. However, the results suggest that the InfoPath list operations could benefit from more than six front-end Web servers. Document library new and open operations have more throughput than InfoPath list new and display operations.

Maximum throughput for new and open operations

Effect of form complexity on throughput

The following table shows the test results of adding form controls to a form template. All results were collected on a farm topology that has four front-end Web servers.

	Baseline solution 1x controls	Baseline solution 2x Controls	Baseline solution 3x controls	Baseline solution 4x controls
Maximum throughput	1484	1424	1310	1201
Green zone	896	834	760	608

The following graph shows the test results of adding form controls to a form template. The number of fields and controls in a form has a significant effect on throughput. These results show that increasing the number of controls by a factor of four can decrease the green zone throughput by more than 30 percent.

Impact of number of controls on throughput

The following table shows the test results of adding form controls to a form template. All results were collected on a farm topology that has four front-end Web servers.

	Baseline solution	Baseline solution without first request optimization	Baseline solution with validation	Baseline solution with 2x validation	Baseline solution with 4x validation
Maximum throughput	1484	1323	1271	1202	1074
Green zone	896	788	724	676	612

The following graph shows the test results of adding validation rules to a form template. The number of validation rules in a form has a measureable effect on throughput. These results show that increasing the number of validation rules by a factor of four can decrease the green zone throughput by more than 30 percent.

Impact of number of validation rules on throughput

Hardware cost per transaction

Maximum RPS of issue tracking display operation

Scorecard dashboard	Scorecard metric	1x1	2x1	4x1	6x1
CPU	Average front-end Web server CPU	91.5%	85.8%	85.8%	81.1%
Reliability	Average page time	0.088	0.093	0.11	0.098
	Failure rate	0%	0%	0%	0%

Green zone RPS of baseline solution new operation

Scorecard dashboard	Scorecard metric	1x1	2x1	4x1	6x1
CPU	Average front-end Web server CPU	44.1%	43.7%	46.5%	46.5%
Reliability	Average page time	0.024	0.025	0.027	0.033
	Failure rate	0%	0%	0%	0%

Maximum RPS of baseline solution new operation

Scorecard dashboard	Scorecard metric	1x1	2x1	4x1	6x1
CPU	Average front-end Web server CPU	93.7%	91.1%	77.5%	54.0%
Reliability	Average page time	0.048	0.050	0.052	0.056
	Failure rate	0%	0%	0%	0%

Green zone RPS of baseline solution save operation

Scorecard dashboard	Scorecard metric	1x1	2x1	4x1	6x1
CPU	Average front-end Web server CPU	40.8%	41.3%	37.3%	24.2%
Reliability	Average page time	0.059	0.074	0.099	0.10
	Failure rate	0%	0.21%	0.0014%	0%

Maximum RPS of baseline solution save operation

Scorecard dashboard	Scorecard metric	1x1	2x1	4x1	6x1
CPU	Average front-end Web server CPU	85.8%	76.8%	-	-
Reliability	Average page time	0.090	0.12	-	-
	Failure rate	0%	0.18%	-	-

Green zone RPS of baseline solution document library submit operation

Scorecard dashboard	Scorecard metric	1x1	2x1	4x1	6x1
CPU	Average front-end Web server CPU	40.6%	44.9%	35.9%	-
Reliability	Average page time	0.061	0.079	0.11	-
	Failure rate	0%	0%	0%	-

Maximum RPS of baseline solution document library submit operation

Scorecard dashboard	Scorecard metric	1x1	2x1	4x1	6x1
CPU	Average front-end Web server CPU	89.1%	74.8%	-	-
Reliability	Average page time	0.11	0.12	-	-
	Failure rate	0.0022%	0%	-	-

Green zone RPS of baseline solution with Web service submit operation

Scorecard dashboard	Scorecard metric	1x1	2x1	4x1	6x1
CPU	Average front-end Web server CPU	45.0%	44.0%	43.8%	46.0%
Reliability	Average page time	0.040	0.042	0.046	0.059
	Failure rate	0%	0%	0.00074%	0%

Maximum RPS of baseline solution with Web service submit operation

Scorecard dashboard	Scorecard metric	1x1	2x1	4x1	6x1
CPU	Average front-end Web server CPU	91.8%	91.4%	74.6%	48.9%
Reliability	Average page time	0.076	0.080	0.091	0.11
	Failure rate	0%	0%	0%	0%

Green zone RPS of baseline solution with five document library submit operations

Scorecard dashboard	Scorecard metric	1x1	2x1	4x1	6x1
CPU	Average front-end Web server CPU	38.4%	39.8%	40.8%	-
Reliability	Average page time	0.070	0.077	0.10	-
	Failure rate	0%	0%	0%	-

Maximum RPS of baseline solution with document library with five submit operations

Scorecard dashboard	Scorecard metric	1x1	2x1	4x1	6x1
CPU	Average front-end Web server CPU	88.4%	80.5%	44.3%	29.7%
Reliability	Average page time	0.12	0.16	0.12	0.12
	Failure rate	0%	0%	0.000011%	0%

Green zone RPS of baseline solution open operation

Scorecard Dashboard	Scorecard metric	1x1	2x1	4x1	6x1
CPU	Average front-end Web server CPU	39.2%	45.8%	45.5%	46.2%
Reliability	Average page time	0.036	0.038	0.041	0.049
	Failure rate	0%	0%	0%	0%

Maximum RPS of baseline solution open operation

Scorecard dashboard	Scorecard metric	1x1	2x1	4x1	6x1
CPU	Average front-end Web server CPU	90.6%	90.6%	82.1%	60.0%
Reliability	Average page time	0.063	0.067	0.069	0.084
	Failure rate	0%	0%	0%	0%

Green zone RPS of issue tracking display operation

Scorecard dashboard	Scorecard metric	1x1	2x1	4x1	6x1
CPU	Average front-end Web server CPU	44.8%	45.4%	44.6%	46.4%
Reliability	Average page time	0.061	0.067	0.073	0.072
	Failure rate	0%	0%	0%	0%

Maximum RPS of issue tracking display operation

Scorecard dashboard	Scorecard metric	1x1	2x1	4x1	6x1
CPU	Average front-end Web server CPU	91.5%	85.8%	85.8%	81.1%
Reliability	Average page time	0.088	0.093	0.11	0.098
	Failure rate	0%	0%	0%	0%

Green zone RPS of issue tracking edit operation

Scorecard dashboard	Scorecard metric	1x1	2x1	4x1	6x1
CPU	Average front-end Web server CPU	45.7%	43.6%	45.1%	60.0%
Reliability	Average page time	0.086	0.090	0.10	0.11
	Failure rate	0%	0%	0%	0%

Green zone RPS of issue tracking display operation

Scorecard dashboard	Scorecard metric	1x1	2x1	4x1	6x1
CPU	Average front-end Web server CPU	89.8%	87.2%	82.9%	79.3%
Reliability	Average page time	0.12	0.13	0.13	0.14
	Failure rate	0%	0%	0.00092%	0.012%

Maximum RPS of issue tracking display operation

Scorecard dashboard	Scorecard metric	1x1	2x1	4x1	6x1
CPU	Average front-end Web server CPU	91.5%	85.8%	85.8%	81.1%
Reliability	Average page time	0.088	0.093	0.11	0.098
	Failure rate	0%	0%	0%	0%

Green zone RPS of issue tracking new operation

Scorecard dashboard	Scorecard metric	1x1	2x1	4x1	6x1
CPU	Average front-end Web server CPU	44.8%	42.9%	40.9%	50.5%
Reliability	Average page time	0.072	0.076	0.089	0.097
	Failure rate	0%	0%	0%	0%

Maximum RPS of issue tracking new operation

Scorecard dashboard	Scorecard metric	1x1	2x1	4x1	6x1
CPU	Average front-end Web server CPU	92.6%	89.2%	85.1%	84.9%
Reliability	Average page time	0.12	0.12	0.12	0.14
	Failure rate	0%	0%	0%	0%

Green zone RPS of baseline solution with controls

Scorecard dashboard	Scorecard metric	1x	2xControls	3xControls	4xControls
CPU	Average front-end Web server CPU		43.9%	49.8%
Reliability	Average page time		0.050	0.054
	Failure rate		0%	0%

Maximum RPS of baseline solution with controls

Scorecard dashboard	Scorecard metric	1x	2xControls	3xControls	4xControls
CPU	Average front-end Web server CPU		79.2%	80.9%	80.2%
Reliability	Average page time		0.098	0.12	0.12
	Failure rate		0%	0%	0.00056%

Green zone RPS of baseline solution validation operation

Scorecard dashboard	Scorecard metric	Without first request optimization	1xValidation	2xValidation	4xValidation
CPU	Average front-end Web server CPU	45.4%	44.7%	45.5%	46.3%
Reliability	Average page time	0.055	0.057	0.061	0.068
	Failure rate	0%	0%	0.19%	0%

Maximum RPS of baseline solution validation operation

Scorecard dashboard	Scorecard metric	Without first request optimization	1xValidation	2xValidation	4xValidation
CPU	Average front-end Web server CPU	80.4%	82.4%	86.8%	85.2%
Reliability	Average page time	0.10	0.11	0.13	0.11
	Failure rate	0.0015%	0%	0%	0.00055%

Recommendations

This section provides general performance and capacity recommendations. Use these recommendations to determine the capacity and performance characteristics of the starting topology that you created to decide whether you have to scale out or scale up the starting topology.

Hardware recommendations

For specific information about minimum and recommended system requirements, see Hardware and software requirements (SharePoint Server 2010).

Note

Memory requirements for Web servers and database servers depend on the size of the farm, the number of concurrent users, and the complexity of features and pages in the farm. You should carefully monitor memory use in order to determine whether more memory must be added.

Scaled-up and scaled-out topologies

To increase the capacity and performance of one of the starting-point topologies, you can either scale up by increasing the capacity of your existing server computers, or scale out by adding additional servers to the topology. This section describes the general performance characteristics of several scaled-out topologies. The sample topologies represent the following common ways to scale out a topology for an InfoPath Forms Services scenario:

• To provide for more user load, add Web server computers.

• To provide for more data load, add capacity to the database server role by increasing the capacity of a single (clustered or mirrored) server, by upgrading to a 64-bit server, or by adding clustered or mirrored servers.

• Maintain a ratio of no more than eight Web server computers to one (clustered or mirrored) database server computer. Although testing in our lab yielded a specific optimum ratio of Web servers to database servers for each test scenario, deployment of more robust hardware, especially for the database server, may yield better results in your environment.

Estimating throughput targets

Many factors can affect throughput. Each of these factors can have a major effect on farm throughput. You should carefully consider each of these factors when you plan your deployment. These factors include the following:

• Number of users

• The type, complexity, and frequency of user operations

• The number of postbacks in an operation

• The performance of data connections

SharePoint Server 2010 can be deployed and configured in a wide variety of ways. As a result, there is no simple way to estimate how many users can be supported by a given number of servers. Therefore, make sure that you conduct testing in your own environment before you deploy SharePoint Server 2010 in a production environment.

Optimizations

The following sections discuss methods for improving farm performance by optimizing form templates and the database server.

Form template design optimizations

• Optimize the first request, that is, the request to open the form, for form templates that do not have onLoad events or business logic. Optimize the first request by delaying the creation of session-state entry in the database until a POST occurs. For such form templates, if the only POST was to close the form after a submit operation, the SQL session state will not be created. To apply this optimization, the form designer must set the Submit advanced setting to close the form after the submit operation. For more information about form template design optimizations, see the six-part blog series at Designing browser-enabled forms for performance in InfoPath Forms Services (https://go.microsoft.com/fwlink/p/?LinkId=129548).

• If a scenario involves saving a form to a document library, it is better to submit the form to the library instead of saving it. A submit operation triggers only one POST request or round trip, whereas a save operation triggers two POST requests. The name of the form can be dynamically generated by using a rule or by using a control in the form.

• Document library forms can achieve greater throughput than InfoPath list forms. If high throughput is needed for a solution, consider using a document library form instead of an InfoPath list form.

• Form complexity, such as the number of controls and amount of form logic, affects throughput. As form complexity increases, the front-end Web server CPU cost also increases. Therefore, more complex forms need more front-end Web servers to achieve greater throughput.

• To reduce user latency, we recommend that the form designer reduce the number of controls per view. For first-page view optimization, position controls that have a high resource cost, such as rich text fields, in subsequent views instead of in the default view.

Common bottlenecks and their causes

During performance testing, several different common bottlenecks were revealed. A bottleneck is a condition in which the capacity of a particular constituent of a farm is reached. This causes a plateau or decrease in farm throughput.

The following table lists some common bottlenecks and describes their causes and possible resolutions.

Troubleshooting performance and scalability

Bottleneck	Cause	Resolution
Database contention (locks)	Database locks prevent multiple users from making conflicting modifications to a set of data. When a set of data is locked by a user or process, no other user or process can modify that same set of data until the first user or process finishes modifying the data and relinquishes the lock.	To help reduce the incidence of database locks, you can: Distribute submitted forms to more document libraries. Scale up the database server. Tune the database server hard disk for read/write. Methods exist to circumvent the database locking system in Microsoft SQL Server 2005, such as the NOLOCK parameter. However, we do not recommend or support use of this method due to the possibility of data corruption.
Database server disk I/O	When the number of I/O requests to a hard disk exceeds the disk’s I/O capacity, the requests will be queued. As a result, the time to complete each request increases.	Distributing data files across multiple physical drives allows for parallel I/O. The blog SharePoint Disk Allocation and Disk I/O (https://go.microsoft.com/fwlink/p/?LinkId=129557) contains useful information about resolving disk I/O issues.
Web server CPU use	When a Web server is overloaded with user requests, average CPU use will approach 100 percent. This prevents the Web server from responding to requests quickly and can cause timeouts and error messages on client computers.	This issue can be resolved in one of two ways. You can add more Web servers to the farm to distribute user load, or you can scale up the Web server or servers by adding higher-speed processors.

Performance monitoring

To help you determine when you have to scale up or scale out a system, use performance counters to monitor the health of the system. Use the information in the following tables to determine which performance counters to monitor, and to which process the performance counters should be applied.

Web servers

The following table shows performance counters and processes to monitor for Web servers in your farm.

Performance counter	Apply to object	Notes
Processor time	Total	Shows the percentage of elapsed time that this thread used the processor to execute instructions.
Memory use	Application pool	Shows the average use of system memory for the application pool. You must identify the correct application pool to monitor. The basic guideline is to identify peak memory use for a given Web application, and assign that number plus 10 to the associated application pool.

Database servers

The following table shows performance counters and processes to monitor for database servers in your farm.

Performance counter	Apply to object	Notes
Average disk queue length	Hard disk that contains SharedServices.mdf	Average values greater than 1.5 per spindle indicate that the write times for that hard disk are insufficient.
Processor time	SQL Server process	Average values greater than 80 percent indicate that processor capacity on the database server is insufficient.
Processor time	Total	Shows the percentage of elapsed time that this thread used the processor to execute instructions.
Memory use	Total	Shows the average use of system memory.

See Also

Other Resources

InfoPath Forms Services 2010 Web Testing Toolkit