Why an "old school" server model, though? Is there a particular user need that requires a traditional drive mapping paradigm using protocols like NFS/SMB/AFP
What about using "serverless" utility object storage like Amazon S3 with odrive as a user front-end?
* You can facilitate native Windows Explorer/Mac Finder integration with selective sync
* You will benefit from the attributes of S3 storage (scalable, durable, secure, redundant, etc.. etc...)
* You can use Amazon IAM, separate buckets, or even odrive Spaces to manage user access
* You can enable versioning to allow recovery of deleted items