Until recently I have been a fan of storing files, uploaded through my web applications, on the disk. However lately I find myself moving more towards storing the files in the database as it's more flexible and easier to maintain. Below are some pros and cons.
Storing files on the disk:
- Performance - faster to retrieve files from the disk than a database.
- Anyone having access to the disk can read and modify files, no need for an additional interface.
- Harder to implement security on single files.
- Time consuming to do backups when there are thousands of files.
Storing files in a database:
- Web/database-farm support - easy to keep two or more databases up to date through replication.
- Handling security is a cake - when getting the file use join/exists to query the user/role table to check for read access, if no read access return nothing.
- More convenient to have all the data located in a single database file.
- Performance - one or more queries against the database are needed in order to get the file, 20 images on a webpage means 20+ queries. Network traffic can also become a bottleneck if the database is running on a seperate server.
- Cost - on shared webhosts, database space is usually more expensive than diskspace.
Conclusion:If you need security checks, replication and don't want thousands of files on your disks, store the files in a database, otherwise store it on the disk.