file synchronization solutions

I have two servers connected via Internet (NOT IN THE SAME LAN) serving the same website (http://www.ourexample.com).The problem is files uploaded on serverA and serverB cannot see each other immediately,thus rsync with certain intervals is not a good solution.
Can anybody give me some advice on the following options?

1.NFS over Internet for file sharing
2.sshfs
3.inotify(our system's kernel does not support this and we donot want to risk upgrading our kernel as well)
4.drbd in active-active mode
5 or any other solutions

Any suggestions will be welcomed.
Thank you in advance.

Comments

[atif.ghaffar]

How are the files uploaded?

If it is custom software then add the logic of syncronizing the file on upload.
If it is by FTP, use something like pure-ftpd with upload-script so it can do the sync for you.

Its a fairly simple problem and there should be more than a few solutions.

let me know if you need more help.

best regards
--
Atif

[Debasish PRamanik]

Couple of solutions

1. Can the uploaded file be stored on a shared drive.
2. If its Windows 2003 server then DFS can be of good help to you.
Regards,
Debasish

[xufengnju]

the files are uploaded by users via http POST method and I want to make the files uploaded from A-site seen by users on B-site immediately.(A-site and B-site are not in A LAN)

[Anonymous]

Like Atif.Ghaffar suggest make the application running on the webserver to the upload to the other server for you.
Something like: files is uploaded on serverA and in the same function (be it php, java or whatever) do a:
"scp uploaded_file root@serberB:/path/to/where/you/put/it"