SharePoint 2010: File Storage System
Introduction
SharePoint provides us a nice UI (User Interface) for saving and retrieving documents. But what happens behind the scenes? Where does SharePoint actually store these files?
File System or Content Database
Opening a document library in windows explorer view allows you to delete, update and add files as we do in the normal file system. Does this mean that files are stored in a physical location? By default, no. All documents are stored in a SQL database called a Content Database as BLOBs (Binary Large Objects).
Some questions that come to mind when storing documents in a database; What if my file size is big? Will it slow down the performance of the SQL Server? I have files that are over 2GB (there is a maximum file size limit of 2GB imposed by IIS Server, that SharePoint has to adhere to), what are my options?
Benefits of Storing Documents in a Content Database
- Easily enable versions
- Enable publishing and approval features (draft, published, minor, major, etc).
- Easily assign metadata to documents (for better search results)
- Apply document management policies (expiry, retention, etc.).
- Integrate document process workflows
Disadvantages of Storing Documents in a Content Database
- SQL Servers are more expensive to maintain, compared with traditional file based storage
- Potentially large database sizes can make restoring SharePoint content databases timely
RBS (Remote Blob Storage)
With the release of SharePoint 2010, you have the option to configure store BLOBs on the physical file system. In SQL Server 2008 (including express), Microsoft provides an add-on feature pack called Remote Blob Storage (RBS (X64 Package X86 Package IA64 Package)). When SharePoint is configured to use RBS, all BLOBs over a configured size are written to the physical file system. This process is hidden from end user. The end user has the same Content Management experience as with content database storage.
Important Note: BLOB metadata is stored in SQL Server database and BLOB is stored in RBS store. Direct access and modification to RBS store is strictly prohibited even via third party tools. All access must occur by using SharePoint 2010 products only.