Web Farm and Web Garden Support

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File Upload Support in a Web Farm and Web Garden

This topic describes how to implement file upload functionality in a clustered web environment (also known as a Web Farm or a Web Garden).

A Web Farm hosts a web application on multiple web servers, whereas a Web Garden runs an application on the same server - but in different worker processes. In a Web Garden, each worker process is executed on its own processor - specified by the Internet Information Services (IIS) settings of the server host where the application is deployed.

To implement file upload on a Web Farm or a Web Garden, customize the following settings.

Website Settings

The machineKey element in the Web.config file should have the same settings for all websites in a Web Farm or Web Garden. Refer to the following Microsoft article for more information: How To: Configure MachineKey in ASP.NET 2.0.

Web Control Settings

If an instance of a website on a Web Farm/Web Garden uses an individual file system, utilize the following options to specify the file system parts that are shared for all website instances in the clustered web environment.

  1. Use the following settings to configure a temporary folder to store uploaded files.

    Web Control

    Settings

    UploadControl

    The UploadControlSettings.AdvancedModeSettings.TemporaryFolder property is not used by default. It is used when the UploadControlSettings.UploadMode property value is set to “Advanced” or “Auto”, and the UploadControlSettings.UploadStorage property value is set to “NotSet” or “FileSystem”.

    The following code snippets illustrate how to specify the UploadControlSettings.AdvancedModeSettings.TemporaryFolder property.

    ...
    UploadControlSettings.AdvancedModeSettings.TemporaryFolder = "//folder1"
    
    ...
    //The "z" drive refers to a network folder. 
    UploadControlSettings.AdvancedModeSettings.TemporaryFolder = "z:\folder"    
    

    FileManager

    The FileManagerSettings.SettingsUpload.AdvancedModeSettings.TemporaryFolder property is used by default when the FileManagerSettingsUpload.UseAdvancedUploadMode property is set to "true".

    HtmlEditor

    The properties listed below are used by default when the ASPxHtmlEditorUploadSettingsBase.UseAdvancedUploadMode property of a specific selector is set to "true":

    The following properties are used by default when the ASPxHtmlEditorUploadSettingsBase.UseAdvancedUploadMode property of a specific dialog is set to "true":

    Spreadsheet

    The SpreadsheetSettings.SettingsDocumentSelector.UploadSettings.AdvancedModeSettings.TemporaryFolder property is used by default when the ASPxHtmlEditorUploadSettingsBase.UseAdvancedUploadMode property is set to "true".

    RichEdit

    The RichEditSettings.SettingsDocumentSelector.UploadSettings.AdvancedModeSettings.TemporaryFolder property is used by default when the ASPxHtmlEditorUploadSettingsBase.UseAdvancedUploadMode property is set to "true".

    BinaryImage

    The BinaryImageSettings.EditingSettings.UploadSettings.TemporaryFolder property is used by default when the BinaryImageUploadSettings.UploadMode property is set to "Auto".

  2. Use the following settings to configure the folder that is used to store files after upload.

    Web Control

    Settings

    UploadControl

    The UploadControlFileSystemSettings.UploadFolder property is not used by default. It is in effect, however, when the UploadControlSettings.UploadStorage property is set to "FileSystem".

    HtmlEditor

    Customize the following properties if the ASPxHtmlEditorUploadSettingsBase.UploadStorage property is set to "FileSystem" for a specific dialog.

Binary Storage Configuration

This topic describes how DevExpress Capcha, Chart, Gauges and BinaryImage components support the IIS clustered web environment (also known as a Web Farm or a Web Garden).

A Web Farm hosts a web application on multiple web servers, whereas a Web Garden runs an application on the same server - but in different worker processes. In a Web Garden, each worker process is executed on its own processor - specified by the Internet Information Services (IIS) settings of the server host where the application is deployed.

A Web Garden specifies multiple worker processes for an application pool that yields the following advantages.

  • Robust request processing: when a worker process in an application pool is busy (e.g., when a script engine stops responding), other worker processes can accept and process requests for the application pool.
  • Reduced resource competition: when a Web Garden reaches a steady state, each new TCP/IP connection is assigned to a worker process (within the Web Garden) based on a round-robin load distribution. This balances workloads and reduces competition for resources that are bound to a worker process.

Under default settings, a binary storage mechanism does not work with Web Farms or Web Gardens for enhanced binary image transformation from a specified binary storage to the client.

To utilize Web Farms and Web Gardens, use a component's BinaryStorageMode property, the BinaryStorageConfigurator.Mode field, and BinaryStorageConfigurator.RegisterCustomStorageStrategy and BinaryStorageConfigurator.RegisterStorageStrategy methods to modify binary storage settings.

The BinaryStorageMode property provides the following modes.

Value Description
Default Uses the Cache mode if a configuration is not defined by the BinaryStorageConfigurator.Mode field.
Session Stores binary data within a session. Web Gardens and Web Farms can be used by the binary storage mechanism if an application session is configured with the SQL Server or State Server Session-State Mode.
Cache Binary data is stored within a cache. Web Gardens and Web Farms will not work correctly in this mode.
Custom Custom mode provides for implementing a custom scenario for storing and accessing binary data. Web Farms and Web Gardens should work if the custom configuration implements storing the binary data on the hard drive, or by using a web service. For more details, use the How to Define Custom Binary Storage Configuration Code Central example, which implements storing binary images on a hard drive.

Note that to specify the binary storage mode for DevExpress Capcha, Chart, Gauges and BinaryImage components simultaneously, define the BinaryStorageMode property within the Global.asax file as shown below:

void Application_Start(object sender, EventArgs e) {
    DevExpress.Web.BinaryStorageConfigurator.Mode = DevExpress.Web.BinaryStorageMode.Session;
}