我已经使用log4net一段时间了，所以我对它并不陌生。但这是我第一个在Windows Server 2008 R2 64位机器上部署的较大的.NET 4.0解决方案。
当然，我首先进行搜索，并找到了类似的主题。其中一个主题听起来非常相似 - 运行Release模式下构建的.Net 4.0 Windows应用程序时，log4net不记录日志 - 但我的问题还是有所不同。
我的解决方案的一部分是一个利用log4net的控制台应用程序。在切换到发布版本后，一切都正常工作。在我电脑上的测试中仍然正常工作。但是在服务器端，log4net将无法工作。
因此，我启用了log4net内部调试。这指向一个存储库冲突。我从未深入研究过log4net，以充分理解它。但问题似乎在于它首先为域程序集（CRMFacade.Domain）创建一个存储库，然后尝试为控制台应用程序（CRMFacade.DataImport）创建一个存储库。这会失败，因为已经存在默认存储库：
log4net: log4net assembly [log4net, Version=1.2.10.0, Culture=neutral, PublicKeyToken=1b44e1d426115821]. Loaded from [Global Assembly Cache]. (.NET Runtime [4.0.30319.225] on Microsoft Windows NT 6.1.7601 Service Pack 1)
log4net: DefaultRepositorySelector: defaultRepositoryType [log4net.Repository.Hierarchy.Hierarchy]
log4net: DefaultRepositorySelector: Creating repository for assembly [CRMFacade.Domain, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]
log4net: DefaultRepositorySelector: Assembly [CRMFacade.Domain, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null] Loaded From [C:\Program Files (x86)\CRMFacade.DataImport\CRMFacade.Domain.dll]
log4net: DefaultRepositorySelector: Assembly [CRMFacade.Domain, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null] does not have a RepositoryAttribute specified.
log4net: DefaultRepositorySelector: Assembly [CRMFacade.Domain, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null] using repository [log4net-default-repository] and repository type [log4net.Repository.Hierarchy.Hierarchy]
log4net: DefaultRepositorySelector: Creating repository [log4net-default-repository] using type [log4net.Repository.Hierarchy.Hierarchy]
log4net: DefaultRepositorySelector: Creating repository for assembly [CRMFacade.DataImport, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]
log4net: DefaultRepositorySelector: Assembly [CRMFacade.DataImport, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null] Loaded From [C:\Program Files (x86)\CRMFacade.DataImport\CRMFacade.DataImport.exe]
log4net: DefaultRepositorySelector: Assembly [CRMFacade.DataImport, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null] does not have a RepositoryAttribute specified.
log4net: DefaultRepositorySelector: Assembly [CRMFacade.DataImport, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null] using repository [log4net-default-repository] and repository type [log4net.Repository.Hierarchy.Hierarchy]
log4net: DefaultRepositorySelector: repository [log4net-default-repository] already exists, using repository type [log4net.Repository.Hierarchy.Hierarchy]
有趣的是：在Debug版本中，控制台应用程序（CRMFacade.DataImport）是log4net创建存储库的第一个且唯一的程序集。在Release版本中，CRMFacade.Domain也是如此。CRMFacade.Domain还从GAC引用log4net以发出日志输出，但它没有log4net配置。这总是由使用该域程序集的程序集提供的。
奇怪的是，在我本地计算机上Release版本仍然可以工作。
为了完整起见，这里是log4net调试输出，一切都正常：
log4net: log4net assembly [log4net, Version=1.2.10.0, Culture=neutral, PublicKeyToken=1b44e1d426115821]. Loaded from [Global Assembly Cache]. (.NET Runtime [4.0.30319.225] on Microsoft Windows NT 6.1.7601 Service Pack 1)
log4net: DefaultRepositorySelector: defaultRepositoryType [log4net.Repository.Hierarchy.Hierarchy]
log4net: DefaultRepositorySelector: Creating repository for assembly [CRMFacade.DataImport, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]
log4net: DefaultRepositorySelector: Assembly [CRMFacade.DataImport, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null] Loaded From [C:\Program Files (x86)\CRMFacade.DataImport\CRMFacade.DataImport.exe]
log4net: DefaultRepositorySelector: Assembly [CRMFacade.DataImport, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null] does not have a RepositoryAttribute specified.
log4net: DefaultRepositorySelector: Assembly [CRMFacade.DataImport, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null] using repository [log4net-default-repository] and repository type [log4net.Repository.Hierarchy.Hierarchy]
log4net: DefaultRepositorySelector: Creating repository [log4net-default-repository] using type [log4net.Repository.Hierarchy.Hierarchy]
log4net: XmlConfigurator: configuring repository [log4net-default-repository] using file [C:\Program Files (x86)\CRMFacade.DataImport\CRMFacade.DataImport.exe.Config]
log4net: XmlConfigurator: configuring repository [log4net-default-repository] using stream
log4net: XmlConfigurator: loading XML configuration
log4net: XmlConfigurator: Configuring Repository [log4net-default-repository]
log4net: XmlHierarchyConfigurator: Configuration update mode [Merge].
log4net: XmlHierarchyConfigurator: Logger [root] Level string is [INFO].
log4net: XmlHierarchyConfigurator: Logger [root] level set to [name="INFO",value=40000].
log4net: XmlHierarchyConfigurator: Loading Appender [ConsoleAppender] type: [log4net.Appender.ConsoleAppender]
log4net: XmlHierarchyConfigurator: Setting Property [LevelMin] to Level value [INFO]
log4net: XmlHierarchyConfigurator: Setting Collection Property [AddFilter] to object [log4net.Filter.LevelRangeFilter]
log4net: PatternParser: Converter [message] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: PatternParser: Converter [newline] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: XmlHierarchyConfigurator: Setting Property [ConversionPattern] to String value [%timestamp [%thread] %-5level %type: %message%newline]
log4net: PatternParser: Converter [timestamp] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: PatternParser: Converter [literal] Option [ [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: PatternParser: Converter [thread] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: PatternParser: Converter [literal] Option [] ] Format [min=-1,max=2147483647,leftAlign=False]
log4net: PatternParser: Converter [level] Option [] Format [min=5,max=2147483647,leftAlign=True]
log4net: PatternParser: Converter [literal] Option [ ] Format [min=-1,max=2147483647,leftAlign=False]
log4net: PatternParser: Converter [type] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: PatternParser: Converter [literal] Option [: ] Format [min=-1,max=2147483647,leftAlign=False]
log4net: PatternParser: Converter [message] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: PatternParser: Converter [newline] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: XmlHierarchyConfigurator: Setting Property [Layout] to object [log4net.Layout.PatternLayout]
log4net: XmlHierarchyConfigurator: Created Appender [ConsoleAppender]
log4net: XmlHierarchyConfigurator: Adding appender named [ConsoleAppender] to logger [root].
log4net: XmlHierarchyConfigurator: Loading Appender [RollingFileAppender] type: [log4net.Appender.RollingFileAppender]
log4net: XmlHierarchyConfigurator: Setting Property [File] to String value [C:\\Logfiles\\APPS\\Corporate\\CRMFacade\\DataImport\\log.txt]
log4net: XmlHierarchyConfigurator: Setting Property [AppendToFile] to Boolean value [True]
log4net: XmlHierarchyConfigurator: Setting Property [RollingStyle] to RollingMode value [Size]
log4net: XmlHierarchyConfigurator: Setting Property [MaxSizeRollBackups] to Int32 value [10]
log4net: XmlHierarchyConfigurator: Setting Property [MaximumFileSize] to String value [2MB]
log4net: XmlHierarchyConfigurator: Setting Property [StaticLogFileName] to Boolean value [True]
log4net: PatternParser: Converter [message] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: PatternParser: Converter [newline] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: XmlHierarchyConfigurator: Setting Property [ConversionPattern] to String value [%date [%thread] %-5level %logger - %message%newline]
log4net: PatternParser: Converter [date] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: PatternParser: Converter [literal] Option [ [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: PatternParser: Converter [thread] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: PatternParser: Converter [literal] Option [] ] Format [min=-1,max=2147483647,leftAlign=False]
log4net: PatternParser: Converter [level] Option [] Format [min=5,max=2147483647,leftAlign=True]
log4net: PatternParser: Converter [literal] Option [ ] Format [min=-1,max=2147483647,leftAlign=False]
log4net: PatternParser: Converter [logger] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: PatternParser: Converter [literal] Option [ - ] Format [min=-1,max=2147483647,leftAlign=False]
log4net: PatternParser: Converter [message] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: PatternParser: Converter [newline] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: XmlHierarchyConfigurator: Setting Property [Layout] to object [log4net.Layout.PatternLayout]
log4net: RollingFileAppender: Searched for existing files in [C:\Logfiles\APPS\Corporate\CRMFacade\DataImport]
log4net: RollingFileAppender: curSizeRollBackups starts at [0]
log4net: FileAppender: Opening file for writing [C:\Logfiles\APPS\Corporate\CRMFacade\DataImport\log.txt] append [True]
log4net: XmlHierarchyConfigurator: Created Appender [RollingFileAppender]
log4net: XmlHierarchyConfigurator: Adding appender named [RollingFileAppender] to logger [root].
log4net: XmlHierarchyConfigurator: Hierarchy Threshold []