Hi,
First, I presented myself. Mahfoud GALFOUT, technical and NOC manager at ISSAL, first Cloud Services Provider in Algeria. I have good knowledge and experience in transition to cloud platforms.
For your case (Or other cases) I prefer starting from the end of your presentation of the project, SECURITY is the most important, both internal and external, mainly if your data are confidential.
Therefore, I recommend hosting the application on your proper servers, secure VPS is good cloud solution. For the storage system, developing a solution is expensive and needs important time. Paid solutions are advanced but expensive (mainly with license/user), so the last solution is to use OpenSource solution, which has these advantages:
- No Cost (Except if server is VPS).
- Advanced and continuous development with active community.
- If needed, at the right time can jump to paid version.
I have a free OpenSource solution for you using , which meets majority of your needs, and more, installed on your own or hosted server. Here is some features:
-Store, Access and Control.
-Mobile and Desktop syncing
-External Storage and Encryption(With Google drive, Dropbox, ...)
-Collaborative Editing
-Versioning and Undelete
-Activity Feed
-Calendars
-Contacts
-Encryption of user files
-User and group administration (via OpenID or LDAP)
-And more technical features...
Regards,
Mahfoud GALFOUT