we will configure script. to rsync archive log file from production db to standby db 

1. How to Rsync over SSH without a password.

a. Log into the TARGET host (standby db), and generate an RSA (public and private) key pair:

target$ ssh-keygen  -t   rsa

* Accept the default location for the key files (press [ENTER]).
* Enter and confirm a pass phrase. (empty for no passphrase) (it is not a requirement)

b. Log into the SOURCE host (production db), and confirm the existence of this file
   "/home/oracle/.ssh./authorized_keys" ,   create this file

source$ touch  ~/.ssh/authorized_keys

c.  Log into the SOURCE host, and get public key from TARGET:

source$ ssh target  cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys

d.  Log into the TARGET host (here is Standby), and try to rsync:

target$ rsync -e ssh -av oracle@source:/ocfs_data/mxdell/arch/  /ocfs_data/mxdell/arch/  

------------------------------------------------------------------ 

改良的脚本，可以判断， 一个linux crontab job在运行，同样的一个如果再次运行会被终止。

#!/bin/bash

pid=`/sbin/pidof rsync`
if [ "$pid" ]
then
    echo "Rsync is already running...."
else
    echo "Starting rsync `date`"
    rsync -e ssh -av oracle@10.13.66.186:/ocfs_data/mxdell/arch/ /ocfs_data/mxdell/arch/
    echo "Completed rsync `date`"
fi
exit 0

-----------------------------------------------------------------

#!/bin/bash

pid=`/sbin/pidof rsync`
if [ "$pid" ]
then
    echo "Rsync is already running...."
else
    echo "Starting rsync `date`"
    rsync -e ssh -av oracle@10.13.67.174:/ocfs_data/mxdell/arch/ /ocfs_data/mxdell/arch/
    echo "Completed rsync `date`"
fi