I would suggest using scp with password-less SSH setup in preference to sftp for automated transfers.

For the first server you could have a cron job running a script every few minutes or so that simply copys the files to server1 and then moves those files out of the way so they don't get sent again, something like:

Code:

scp -pr * server1:/server1directory
mv * ../donedirectory

Then on Server1 do a cron job calling a script that SCPs one file at a time and if successful deletes the local copy of the file, something like:

Code:

ls -laR > listfile
while read FILE; do
  scp ${FILE} server2:/server2directory 2>&1 > /tmp/scp_log_file
  RESULT=$?
  SCPTEST=`egrep -i "error|fail|denied|illegal|no such|error|unexpected|unknown|too long|lost connection" /tmp/scp_log_file`
  if [ ${RESULT} -eq 0 -a -z "${SCPTEST}" ]; then
    rm ${FILE}
  else
    echo "Error: ${FILE} not sent to server2."
  fi
done < listfile