我曾经开发过一个图像处理应用程序。我们将上传的图像存储在类似于/images/[今天的日期]/[id号]的目录中。但是我们还从图像中提取了元数据(exif数据)，并将其连同时间戳等一起存储在数据库中。

关于这个话题，这里有一份有趣的白皮书。

是否使用BLOB:数据库或文件系统中的大型对象存储

答案是“视情况而定。”当然，这取决于数据库服务器及其blob存储方法。它还取决于存储在blob中的数据类型，以及如何访问这些数据。

使用数据库作为存储机制，可以有效地存储和传递较小的文件。较大的文件可能最好使用文件系统存储，特别是如果它们将经常被修改/更新。(blob碎片在性能方面成为一个问题。)

Here's an additional point to keep in mind. One of the reasons supporting the use of a database to store the blobs is ACID compliance. However, the approach that the testers used in the white paper, (Bulk Logged option of SQL Server,) which doubled SQL Server throughput, effectively changed the 'D' in ACID to a 'd,' as the blob data was not logged with the initial writes for the transaction. Therefore, if full ACID compliance is an important requirement for your system, halve the SQL Server throughput figures for database writes when comparing file I/O to database blob I/O.

我负责一些管理许多TB图像的应用程序。我们发现在数据库中存储文件路径是最好的。

这里有几个问题:

database storage is usually more expensive than file system storage you can super-accelerate file system access with standard off the shelf products for example, many web servers use the operating system's sendfile() system call to asynchronously send a file directly from the file system to the network interface. Images stored in a database don't benefit from this optimization. things like web servers, etc, need no special coding or processing to access images in the file system databases win out where transactional integrity between the image and metadata are important. it is more complex to manage integrity between db metadata and file system data it is difficult (within the context of a web application) to guarantee data has been flushed to disk on the filesystem

I have worked with many digital storage systems and they all store digital objects on the file system. They tend to use a branch approach, so there will be an archive tree on the file system, often starting with year of entry e.g. 2009, subdirectory will be month e.g. 8 for August, next directory will be day e.g. 11 and sometimes they will use hour as well, the file will then be named with the records persistent ID. Using BLOBS has its advantages and I have heard of it being used often in the IT parts of the chemical industry for storing thousands or millions of photographs and diagrams. It can provide more granular security, a single method of backup, potentially better data integrity and improved inter media searching, Oracle has many features for this within the package they used to call Intermedia (I think it is called something else now). The file system can also have granular security provided through a system such as XACML or another XML type security object. See D Space of Fedora Object Store for examples.

SQL Server 2008提供了一个两者兼备的解决方案:文件流数据类型。

像管理普通表一样管理它，并具有文件系统的性能。

文件存储上的图像是最好的选择，并将元数据存储在数据库中作为补充。从web服务器的角度来看，提供东西的最快方法是直接指向它。如果它在数据库中——比如Sharepoint——你就有ADO的开销。用网把它拉出来，流出来，等等。

Documentum -虽然臃肿和复杂-有它的权利，文件是在共享和可供您决定如何存储它们-磁盘上的服务器，SAN, NAS，无论什么。Documentum的策略是根据数据库中的主键对文件夹和文件名进行编码，从而将文件存储为树状结构。DB成为了解什么文件是什么文件和加强安全性的资源。对于大容量系统，这种方法是一种很好的方法。

在处理元数据时也要考虑这一点:如果您需要更新元数据语料库的属性，DB是您的朋友，因为您可以使用SQL快速执行更新。使用其他标记系统，您手头没有简单的数据操作工具