Unioning and mirroring file system over the internet
Blue sky thinking at the moment:
I have a number of file servers, each at different sites. I would like to be able to make these appear as one, so that files on any server can be accessed from any site, and the user doesn't even see there are multiple servers.
Obviously, the internet is slow, especially the upload speeds. So when a file is written the write ought to go to the server on the client's LAN - even if it was previously on another of the servers.
However, for robustness, some sort of background mirroring is also wanted. If all the servers were left on and connected, they eventually end up all in sync. But this mirroring needs to be mindful of bandwidth usage; if someone writes a big file to their local server, copying that to the other servers can't interfere with normal internet usage.
I think UnionFS or similar might be able to handle the unioning side, but not the mirroring stuff.
Any thoughts on doing this?