Referencing resources in SharePoint: File system or content database?

Recently I’ve gone through a particular project and modified the solution structure and philosophy behind deploying resources for use within a number of public facing SharePoint sites. It’s a concept I actually hadn’t given too much thought to in the past – previously the majority of projects I’ve worked on or created have simply deployed all resources to the /_layouts/ folder and that was that. There are varying reasons why you would choose one method over the other and a discussion on these will form the basis for this post.

First though a bit of background on what brought this topic to the fore. The project I was analysing was a shared solution used for a large number of public facing websites (5+) hosted on the MOSS platform. All resources (CSS, Images, JavaScript, Flash) were deployed to the 12 hive within a folder structure suitable for identifying the site the resources belonged to. There were some smarts in the code which determined where to reference the resources in question.

The problem was 3-fold. Firstly, some site owners wanted the ability to make changes to the CSS or images themselves and didn’t have access to the servers to do so. Secondly, even if the changes were to be made by the development team they still needed to be done within the weekly change window to deploy the new solution. Finally, because the solution was shared between a number of sites and contained code as well as resources, any minor changes made to an image or CSS file would need to go through a complete and rigorous UAT and regression testing phase before they could be deployed.

The solution was obvious; the resources needed to be stored in the content database, and there are a number of benefits gained from storing resources for SharePoint in there.

  1. Site owners can be given the ability to make modifications to the images and CSS files if desired. Assuming they don’t have access to the server itself, and they shouldn’t, getting the files into the content database is the best way to enable this.
  2. Immediate access. Assuming you’re deploying your resources to the file system via a solution package (and there should be no other option), you’ll require the solution to be deployed and in many cases this needs to be scheduled during a deployment window.
  3. Versioning. Storing these files within the content database will be able to leverage the in-built versioning capabilities of SharePoint assuming they’re enabled. This could be countered with the fact that source control could be considered a form of file versioning.
  4. Backups. This in my opinion is somewhat of a minor benefit as any decent disaster recovery plan would incorporate multiple forms of backup which would include source control and the SharePoint server (assuming virtual environments), however having the files in the content database enables the resources to be backed up both via SharePoint mechanisms and via backups of the SQL database.
  5. Isolation. By storing the files within the content database you’re ensuring that any changes made are far less likely to affect other sites hosted on the same server. Storing the files within separate sub-folders on the file system mitigates this to an extent, but it’s less safe.
  6. Sandboxed solutions. While not relevant to my own situation in MOSS, deploying the resources to the content database enables the solution to be deployed as a sandboxed solution, opening the door to deploying in a hosted environment.

So why would anyone want to deploy their resources to the file system in the first place? I’m going to start by being cynical – developer laziness. Frankly, with tools such as WSPBuilder in 2007 or the build-in developer tools in 2010 it’s simply easier to place your resources into a mapped folder in your solution rather than creating the feature and module to deploy the files to the content database. There are however legitimate reasons why you may want to go down this path.

  1. Global access. It is possible that some of the resources you are deploying need to be used across sites for the purpose of common branding. By deploying to the file system all sites will have access to the files without having to duplicate content into the individual content databases.
  2. Restricting access. While the granular security in SharePoint allows you to lock down access quite significantly, there is the possibility that a user may have levels of access which would give them the ability to modify these resources when they shouldn’t. It would be a bad security scheme that enabled this, but keeping the files out of the content database and on the file system would ensure this never happened.
  3. Performance. Out of the box you’d get better performance having the resources on the file system rather than the content database. You can get around this for the most part using the build-in caching mechanisms within SharePoint such as BLOB caching, however for MOSS at least there are known issues associated with this noted in Chris O’Brien’s post on Optimization, BLOB caching and HTTP 304s.

It’s a question that seems to polarise the SharePoint community and there are a bunch of blog posts, MSDN articles and discussions on this very subject matter. My personal opinion now, which would appear to be backed by a number of credible posts I’ve since read, is that ideally resources for SharePoint should be stored in the content database whenever possible.

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