End users' attraction to Google Drive is built on one key concept: "I can access my files from anywhere." End users who have been paying attention in your security training also like the fact that all connections to Google Drive are secured with HTTPS.
However, Google Drive, er, drives IT administrators nuts because it encourages people to send critical business documents to an untrusted provider. This isn't just paranoia - it's actually baked into Google's terms of service (TOS).
According to the TOS, Google will not take away any "intellectual property rights" your business claims on its own files. However, the same TOS permits Google to "use...reproduce, modify, create derivative works, communicate, publish, publicly perform, publicly display and distribute such content." $100 says that's not the same policy you offer on your SAN storage.
SolarWinds Alternative to Google Drive
1) Install Serv-U MFT in your data center, private cloud, or other system under IT's control. (Did we mention it can run on Windows or Linux?)
2) Point Serv-U MFT to your Active Directory. This allows your employees and contractors to authenticate using their existing credentials and saves you the trouble of having to duplicate their accounts on Serv-U. (You can also create additional Serv-U accounts for customers and partners without accounts on Serv-U.)
3) Point Serv-U MFT to your primary NAS or other shared storage (often, wherever you keep your users' home folders or corporate documents). This allows people to securely access the same material they would in the office from anywhere in the world.
4) Instruct your users to connect to "https://yourserver/" using the browser, tablet or mobile device of their choice. After they sign on with their usual credentials, your users will be able to work with the same files they use in the office.