website data mirroring or UID, GID sync in /etc/{group,passwd}
It would be good to have website data mirroring from server1 to server2, whenever a user uploads www data. Using NFS is difficult since ISPConfig doesn't keep the same UID and GID in /etc/{passwd,group} between "mirrored" servers. Or simply keeping /etc/{passwd,group} and other files completely in sync as far as UID's and GID's go.