Exchange 体系结构Exchange architecture

Exchange 使用一个构建基块体系结构,提供电子邮件服务,以便在各种规模的组织(从小型组织到最大规模的跨国企业)进行部署。这种体系结构如下图所示。Exchange use a single building block architecture that provides email services for deployments at all sizes, from small organizations to the largest multi-national corporations. This architecture is describe in the following diagram.

Exchange 体系结构

下面的部分分别介绍了各个组成部分。Individual components are described in the following sections.

服务器通信体系结构Server communication architecture

Exchange 服务器与过去和将来的 Exchange 版本之间的通信发生在协议层。不允许跨层通信。我们将这种通信体系结构概括为"每个服务器都是一座'岛屿'"。这种体系结构具有以下优势:Communication between Exchange servers and past and future versions of Exchange occurs at the protocol layer. Cross-layer communication isn't allowed. This communication architecture is summarized as "every server is an island". This architecture has the following benefits:

  • 减少服务器间通信。Reduced inter-server communications.

  • 提供版本感知通信。Version-aware communications.

  • 隔离故障。Isolated failures.

  • 在每个服务器内集成设计。Integrated design inside each server.

Exchange 服务器之间的协议层通信如下图所示。Protocol layer communication between Exchange servers is shown in the following diagram.

Exchange 服务器之间的通信

服务器角色体系结构Server role architecture

Exchange 使用邮箱服务器和边缘传输服务器。下面的部分分别介绍了这些服务器角色。Exchange uses Mailbox servers and Edge Transport servers. These server roles are described in the following sections.

邮箱服务器Mailbox servers

  • 邮箱服务器包含用于路由邮件的传输服务。有关详细信息,请参阅邮件流和传输管道Mailbox servers contain the transport services that are used to route mail. For more information, see Mail flow and the transport pipeline

  • 邮箱服务器包含处理、呈现和存储数据的邮箱数据库。有关详细信息,请参阅管理 Exchange Server 中的邮箱数据库Mailbox servers contain mailbox databases that process, render, and store data. For more information, see Manage mailbox databases in Exchange Server.

  • 邮箱服务器包含接受所有协议的客户端连接的客户端访问服务。这些前端服务负责将连接路由或代理到邮箱服务器上的相应后端服务。客户端不直接连接到后端服务。有关详细信息,请参阅本主题后面介绍的客户端访问协议体系结构部分。Mailbox servers contain the Client Access services that accept client connections for all protocols. These frontend services are responsible for routing or proxying connections to the corresponding backend services on a Mailbox server. Clients don't connect directly to the backend services. For more information, see the Client Access protocol architecture section later in this topic.

  • 在 Exchange 2016 中,邮箱服务器包含向邮箱提供语音邮件和其他电话服务功能的统一消息 (UM) 服务。In Exchange 2016, Mailbox servers contain the Unified Messaging (UM) services that provide voice mail and other telephony features to mailboxes.

    备注

    统一消息在 Exchange 2019 中不可用。Unified Messaging is not available in Exchange 2019.

  • 可以使用 Exchange 管理中心 (EAC) 和 Exchange 命令行管理程序来管理邮箱服务器。有关详细信息,请参阅 Exchange Server 中的 Exchange 管理中心Exchange Server PowerShell(Exchange 命令行管理程序)You manage Mailbox servers by using the Exchange admin center (EAC) and the Exchange Management Shell. For more information, see Exchange admin center in Exchange Server and Exchange Server PowerShell (Exchange Management Shell).

边缘传输服务器Edge Transport servers

  • 边缘传输服务器处理 Exchange 组织的所有外部邮件流。Edge Transport servers handle all external mail flow for the Exchange organization.

  • 边缘传输服务器通常安装在外围网络中,并订阅到内部 Exchange 组织。当 Exchange 组织接收和发送邮件时,EdgeSync 同步进程会向边缘传输服务器提供收件人信息和其他配置信息。Edge Transport servers are typically installed in the perimeter network, and are subscribed to the internal Exchange organization. The EdgeSync synchronization process makes recipient and other configuration information available to the Edge Transport server as mail enters and leaves the Exchange organization.

  • 当 Exchange 组织接收和发送邮件时,边缘传输服务器会提供反垃圾邮件规则和邮件流规则。有关详细信息,请参阅 Exchange Server 中的反垃圾邮件保护Edge Transport servers provide antispam and mail flow rules as mail enters and leaves your Exchange organization. For more information, see Antispam protection in Exchange Server

  • 通过使用 Exchange 命令行管理程序管理边缘传输服务器。有关详细信息,请参阅 Exchange Server PowerShell(Exchange 命令行管理程序)You manage Edge Transport servers by using the Exchange Management Shell. For more information, see Exchange Server PowerShell (Exchange Management Shell).

有关边缘传输服务器的详细信息,请参阅边缘传输服务器For more information about Edge Transport servers, see Edge Transport servers.

高可用性体系结构High availability architecture

下面的部分分别介绍了 Exchange Server 中的高可用性功能。The high availability features in Exchange Server are described in the following sections.

邮箱高可用性Mailbox high availability

数据库可用性组 (DAG) 是内置于 Exchange Server 的高可用性站点复原框架的基本元素。DAG 是一组邮箱服务器,不仅托管一组数据库,还提供数据库、网络和服务器故障的数据库级自动恢复功能。与 Exchange 2013 相比,Exchange 2016 或更高版本中的 DAG 已进行了改进。有关 DAG 的详细信息,请参阅数据库可用性组A database availability group (DAG) is the fundamental element of the high availability and site resilience framework that's built into Exchange Server. A DAG is a group of Mailbox servers that host a set of databases and provides automatic, database-level recovery from database, network, and server failures. And DAGs in Exchange 2016 or later have been improved compared to Exchange 2013. For more information about DAGs, see Database availability groups.

传输高可用性Transport high availability

  • 传输服务会为传输中的所有邮件创建冗余副本。此功能称为“卷影冗余”**。The Transport service makes redundant copies of all messages in transit. This feature is known as shadow redundancy.

  • 传输服务会为所有已传递的邮件创建冗余副本。此功能称为“安全网络”**。The transport service makes redundant copies of all delivered messages. This feature is known as Safety Net.

  • 在 Exchange Server 中,DAG 表示传输高可用性边界。可以跨多个 Active Directory 站点部署 DAG,从而实现站点复原。In Exchange Server, a DAG represents a transport high availability boundary. You can achieve site resilience by spanning a DAG across multiple Active Directory sites.

  • 在 Exchange Server 中,要实现传输高可用性,不只是需要尽可能确保邮件冗余而已,因为冗余并不取决于发送邮件服务器所支持的功能。因此,可以说,Exchange Server 尝试在邮件传递期间和之后保留邮件的多个副本,以确保邮件冗余。In Exchange Server, transport high availability is more than a best effort for message redundancy, because redundancy doesn't depend on supported features of the sending mail server. Therefore, you can say that Exchange Server attempts to guarantee message redundancy by keeping multiple copies of messages during and after delivery.

有关详细信息,请参阅传输高可用性For more information, see Transport high availability.

客户端访问协议体系结构Client Access protocol architecture

Exchange 邮箱服务器上的客户端访问服务负责接受所有形式的客户端连接。客户端访问(前端)服务将这些连接代理到目标邮箱服务器(保留用户邮箱的主动副本的本地服务器或远程邮箱服务器)上的后端服务。客户端不直接连接到后端服务。这种通信体系结构如下图所示。The Client Access services on Exchange Mailbox servers are responsible for accepting all forms of client connections. The Client Access (frontend) services proxy these connections to the backend services on the destination Mailbox server (the local server or a remote Mailbox server that holds the active copy of the user's mailbox). Clients don't directly connect to the backend services. This communication is shown in the following diagram.

客户端与 Exchange 服务器的通信方式

客户端使用的协议决定了用于将请求代理到目标邮箱服务器上的后端服务的协议。例如,如果客户端使用的是 HTTP 连接,则邮箱服务器使用 HTTP 将请求代理到目标邮箱服务器(使用自签名证书通过 SSL 确保安全)。如果客户端使用的是 IMAP 或 POP,则所使用的协议也是 IMAP 或 POP。The protocol that's used by a client determines the protocol that's used to proxy the request to the backend services on the destination Mailbox server. For example, if the client connected using HTTP, the Mailbox server uses HTTP to proxy the request to the destination Mailbox server (secured via SSL using a self-signed certificate). If the client used IMAP or POP, then the protocol that's used is IMAP or POP.

在 Exchange 2016 中,电话服务请求不同于其他客户端连接。邮箱服务器不会代理请求,而是会将请求重定向到保留用户邮箱的主动副本的邮箱服务器。必须有电话服务设备,才能直接使用统一消息服务在目标 Exchange 2016 邮箱服务器上建立 SIP 和 RTP 会话。In Exchange 2016, telephony requests are different than other client connections. Instead of proxying the request, the Mailbox server redirects the request to the Mailbox server that holds the active copy of the user's mailbox. Telephony devices are required to establish their SIP and RTP sessions directly with the Unified Messaging services on the destination Exchange 2016 Mailbox server.

备注

统一消息在 Exchange 2019 中不可用。Unified Messaging is not available in Exchange 2019.

Exchange 体系结构更改Exchange architecture changes

  • 服务器角色合并:在 Exchange 2013 或更早版本中,你可以在不同的计算机上安装客户端访问服务器角色和邮箱服务器角色。在 Exchange 2016 或更高版本中,客户端访问服务器角色会自动作为邮箱服务器角色的一部分进行安装,客户端访问服务器角色不再是单独的安装选项。这一更改反映了 Exchange 服务器角色归置(自 Exchange 2010 起的推荐最佳做法)的理念。多角色 Exchange 服务器体系结构带来了以下切实可见的好处:Server role consolidation: In Exchange 2013 or earlier, you could install the Client Access server role and the Mailbox server role on separate computers. In Exchange 2016 or later, the Client Access server role is automatically installed as part of the Mailbox server role, and the Client Access server role isn't available as a separate installation option. This change reflects the philosophy of Exchange server role co-location that's been a recommended best practice since Exchange 2010. A multi-role Exchange server architecture gives you the following tangible benefits:

    • 环境中的所有 Exchange 服务器(所有边缘传输服务器可能除外)都可以完全相同,即具有相同的硬件、配置等。这种统一性可简化硬件的购买,以及 Exchange 服务器的维护和管理。All Exchange servers in your environment (with the likely exception of any Edge Transport servers) can be exactly the same: the same hardware, the same configuration, etc. This uniformity simplifies hardware purchasing, and also maintenance and management of the Exchange servers.

    • 您可能需要更少的物理 Exchange 服务器。这不仅能降低日常维护成本,还能减少 Exchange 服务器许可证以及机架、占地面积和供电需求。You'll likely need fewer physical Exchange servers. This results in lower ongoing maintenance costs, fewer Exchange server licenses, and reduced rack, floor space, and power requirements.

    • 可伸缩性得到了改善,因为您要跨更多的物理计算机分布工作负荷。在故障发生期间,其余 Exchange 多角色服务器上的负荷只是逐步增加,这可以确保 Exchange 服务器上的其他功能不会受到不利影响。Scalability is improved, because you're distributing the workload across a greater number of physical machines. During a failure, the load on the remaining Exchange multi-role servers increases only incrementally, which ensures the other functions on the Exchange servers aren't adversely affected.

    • 复原性得到了改善,因为多角色 Exchange 服务器可以从更多的客户端访问角色(或服务)故障中复原,并仍能提供服务。Resiliency is improved, because a multi-role Exchange server can survive a greater number of Client Access role (or service) failures and still provide service.

  • 搜索功能改进:本地搜索实例现在可以从本地邮箱数据库副本中读取数据。因此,被动搜索实例不再需要与主动搜索实例共同协作来执行索引更新,并且与旧版 Exchange 相比,主动副本与被动副本之间的带宽需求已减少了 40%。此外,搜索功能现在可以在用户完成搜索词之前就执行多次异步磁盘读取。这不仅能在高速缓存中填充相关信息,还能提供 Outlook 网页版等联机客户端的次秒级搜索查询延迟。Search improvements: The local search instance is now able to read data from the local mailbox database copy. As a result, passive search instances no longer need to coordinate with their active counterparts to perform index updates, and bandwidth requirements between the active copy and a passive copy have been reduced by 40% compared to previous versions of Exchange. Also, search is now able to perform multiple asynchronous disk reads prior to a user completing a search term. This populates the cache with relevant information, and provides sub-second search query latency for online clients like Outlook on the web.

  • 适用于 Outlook 网页版的 Office Online Server Preview 文档预览:在 Exchange 2013 或更早版本中,Outlook Web App 包含可内置预览 Office 和 PDF 文档的 WebReady Document Viewing。在 Exchange 2016 或更高版本中,Outlook 网页版使用 Office Online Server Preview 提供适用于文档的丰富预览和编辑功能。虽然它提供的文档体验与其他产品(如 SharePoint 和 Skype for Business)一致,但仍必须在本地环境中部署 Office Online Server Preview(如果你尚未部署的话)。有关详细信息,请参阅在 Exchange 组织中安装 Office Online ServerOffice Online Server Preview for Outlook on the web document preview: In Exchange 2013 or earlier, Outlook Web App included WebReady Document Viewing for the built-in preview of Office and PDF documents. In Exchange 2016 or later, Outlook on the web uses Office Online Server Preview to provide rich preview and editing capabilities for documents. While this provides a consistent document experience with other products like SharePoint and Skype for Business, it does require you to deploy Office Online Server Preview in your on-premises environment if you don't already have it. For more information, see Install Office Online Server in an Exchange organization.

  • MAPI over HTTP 是 Outlook 连接的默认方法:MAPI over HTTP 是在 Exchange 2013 Service Pack 1 中引入,在传统 Outlook Anywhere (RPC over HTTP) 连接方法的基础上进行了改进。在 Exchange 2016 或更高版本中,MAPI over HTTP 为默认启用,并提供其他控件(如每个用户启用或禁用 MAPI over HTTP 的功能,以及是否向外部客户端播发它)。有关详细信息,请参阅 Exchange Server 中的 MAPI over HTTPMAPI over HTTP is the default for Outlook connections: MAPI over HTTP was introduced in Exchange 2013 Service Pack 1, and offers improvements over the traditional Outlook Anywhere (RPC over HTTP) connection method. In Exchange 2016 or later, MAPI over HTTP is enabled by default, and offers additional controls, such as the ability to enable or disable MAPI over HTTP per user, and whether to advertise it to external clients. For more information, see MAPI over HTTP in Exchange Server.