WSS3.0 SP1 中EBS综述

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Overview of External BLOB Storage in Windows SharePoint Services
WSS中EBS综述

　　Although Microsoft SQL Server is a highly efficient resource manager for structured data in a SharePoint content database, a large proportion of data files are represented as unstructured binary files—that is, binary large object (BLOB) data files. SQL Server offers less of a gain for binary data than for structured data, so your server farm might gain cost savings by using an external data store to contain your binary data files.
尽管在sharepoint 内容数据库中，微软的Sql server对结构化数据是一个高效的资源管理器，但是大部分的数据文件作为非结构化的二进制文件展现，也就是BLOB数据文件。相对于结构化数据而言，SQL Server 为二进制数据提供了较少的支持，因此你的服务器场通过使用一个外部的数据存储包含你的二进制文件可以节省花费。
Overview
综述

　　SQL Server is a highly performant resource manager for structured data in Windows SharePoint Services. SQL Server provides a fast, efficient SQL query engine and exceptional query-based retrieval of structured data.
在sharepoint 服务中，SQL Server是一个高效的结构化数据资源管理器。SQL Server提供了一个快捷的，有效地SQL 查询引擎 和 结构化数据的异常恢复。
However, a large proportion of data in a typical enterprise deployment of Windows SharePoint Services is stored as unstructured, binary data streams associated with SharePoint files. These binary streams, or BLOBs, which correspond with SharePoint files, often comprise a majority of your data.
但是，在一个典型的wss企业部署中，大部分数据存储为非结构、二进制的数据流。这些二进制流，或BLOBs，与Sharepoint 文件通信，组成了你的数据的主要部分。
　　The problem, however, is that SQL Server is not the best option for storing unstructured binary data streams because unstructured binary data does not expose itself to the rich SQL query environment. In fact, store and retrieve operations for BLOB data in SQL Server are little more than simple get and put statements. Therefore, because BLOB data is not able to leverage one of SQL Server's most useful features, its query engine, its value as a BLOB store is limited.
但是由于非结构化的二进制数据不能将其自身置于丰富的SQL 查询环境，所以SQL Server不是一个存储非结构化二进制数据流的最佳选择。实际上，在SQL Server中，存储和取出BLOB数据的操作无外乎最简单的get和put状态。因此，BLOB数据不能有效地使用SQL Server最有用的特性的任何一个，它的查询引擎。所以在BLOB存储上，SQL Server的价值是有限的。

　　The solution, then, is using a simple, cost-effective storage medium to function as an external BLOB store (EBS). The EBS runs parallel to the site's SQL Server content database, which stores the site's structured data. To coordinate the two data stores, you must implement a COM interface (ISPExternalBinaryProvider), which uses simple semantics to recognize file Save and Open commands and invokes redirection calls to the BLOB store when it recognizes BLOB data streams.

解决方案是使用一个简单的、性价比高的存储媒体作为BLOB的外部存储（EBS）。EBS与站点的SQL Server内容库平行运行，内容库中存储站点的结构化数据。为了协调这两个数据存储，你必须继承一个COM接口(ISPExternalBinaryProvider)，该接口使用简单的语义去识别文件的保存和打开命令，并在识别BLOB数据流时，异步重定向请求一个BLOB存储。
　　When you implement this interface, you can use the object known as the external BLOB store provider—the EBS Provider—which coordinates store and retrieve operations for the BLOB store. The EBS Provider also ensures that the SQL Server content database contains metadata references to their associated BLOB streams in the external BLOB store.
在你继承了该接口时，你能够使用EBSProvider对象，该对象为BLOB存储协调存储和取回操作。EBS Provider 也确保在EBS中，SQL Server内容数据库包含元数据引用与BLOB流的关联。

You must install, register, and configure the EBS Provider on each of the front-end Web servers for each SharePoint site. This allows the interface to recognize Save and Open commands (representing the store and retrieve operations, respectively) and initiate the EBS Provider's redirection calls.
你必须在每一个前端Web Server上，为每一个站点安装、注册和配置EBS Provider。这允许接口识别保存和打开命令(分别表现为存储和取回操作)，并初始化EBS Provider的重定向请求。
　　Be sure to understand that implementing EBS in your deployment requires certain trade-offs. In addition to the operational limits that are summarized in Operational Limits and Trade-Off Analysis, implementing the EBS Provider also adds new support and maintenance requirements.

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