Each instance of ProGet needs its own file storage (S3 bucket, disk, etc). You definitely do not want to use the same storage across instances - that'd cause a major issue.
Some users have been tempted to use a combination of Database Replication + Disk Replication with third-party "external" replication tools, and learned the hard way that it's an absolute disaster once deployed. So don't try that :)
Basically the "external" (non ProGet) replication is way too slow to handle the type of traffic ProGet receives, and the files/database replication cycles are never in sync.
-- Dean
