[Samba] Samba Replication

[Steve Francia]

Hello, I have the following situation:

I have two offices, which both require local speed access to their file
shares. Currently there is a single windows server that provides network
shares to both offices, the remote one through a vpn.

I have used Samba since the early days, and am quite familiar with it's
capabilities and limitations, however I have never tried to perform
replication with it.

My current plan, which certainly has some limitations is to take 2 samba
servers, put one in each office. Rsync the two every half an hour. This will
provide redundancy and solve the major problem at hand, but will introduce
new problems.

30 minutes is too long, and users may work on the same file simultaneously
resulting in a conflict and changes lost.

Has anyone approached this problem before?
What replication options work well with the current stable build of samba?
Is there any way to replicate when a file is locked, so the user will get
the warning that the file is locked?

Any feedback would be helpful, even if it is a link.

Thanks in advance,
Steve Francia