Access, performance, and reliability. They are the tradeoffs to each type.

If you store the files in the database, you have to scale up the database to handle ever increasing data, which also increases the server load. If the database crashes it can be a long nightmare to reconstruct/repair due to the data. Load balancing and sychronizing becomes difficult when the data gets large. BUt you have full control over file security, access rights, the files will always be available, development for access to the files is easier, and file access is faster as they can be indexed.

If files are stored in the filesystem (local, drive, NAS, SAS, etc), you may have dropped links/connections/or concurrent access issues and security rights are also more difficult to enforce. Database recovery and maintianance problems become much easier to deal with, and expanding storage space and redundancy for your files is fairly straight forward. It is also easier to load balance and decenteralize your database to different locations.

There are many more nuances to the pros and cons, in the end it relates to how much data will be handled. If you are handling 1/2 million documents+, you probably should not be storing them in the same database as Odoo/OpenERP, they should live in thier own dedicated database with the proper database type, or they should live in a dedicated fileserver.

Hello,

I do store attachments for a module I developped (Drop Box like) on file system to keep a light DB. I just do not forget to backup storage folder with the DB.