File tree replication in FreeBSD

[Kentucky Mandeloid Mo.]

I'm looking for file replication solution for FreeBSD.

I have a task to replicate about 11G of files with 500k total files count.
I say replication not mirroring i.e. I need to copy modified files to slaves 
almost imidiately after the change. 
Tried to find some ready solution but fails.
There is FAM from SGI but it fails to work properly on FreeBSD (it makes silly 
stat(2) calls).
kevent(2) also don't have anough API to watch >= 500k files.
So I see the only way is to have kernel module that watch kernel calls for 
file operations.

So is there some other points to build a file replication?