iscsi realtime sync

#!/bin/sh
DATE=$(date +"%Y-%m-%d %H:%M:%S")


CLUSTERNAS01=$(/sbin/iscsiadm -m discovery -t st -p xxx.xxx.xxx.xxx)
MOUNT01=$(mount)
MOUNT01_ERG=$(echo $MOUNT01 | grep '/dev/mapper/root_vg01-lv01 on /rootfs type gfs2')
VAR1=$(echo $CLUSTERNAS01 | grep 'xxx.xxx.xxx.xxx:3260,1 iqn.2004-04.com.qnap:ts-459uplus:iscsi.clusternas01.c82106')


MOUNT02=$(mount)
MOUNT02_ERG=$(echo $MOUNT02 | grep '/dev/mapper/root_vg02-lv02 on /rootfs type gfs2')
CLUSTERNAS02=$(/sbin/iscsiadm -m discovery -t st -p xxx.xxx.xxx.xxx)
VAR2=$(echo $CLUSTERNAS02 | grep 'xxx.xxx.xxx.xxx:3260,1 iqn.2004-04.com.qnap:ts-459uplus:iscsi.clusternas02.c8222c')


if [ -n "$VAR1" ]; then


        if [ -n "$MOUNT01_ERG" ]; then


                if [ -n "$MOUNT02_ERG" ]; then


                        umount /rootfs
                        umount /rootfs
                        echo $DATE OK clusternas01 back >> /var/log/check_clusternas.log
                        exit 0


                else


                        echo $DATE OK >> /var/log/check_clusternas.log
                        exit 0


                fi


        else
                echo $DATE switch to clusternas01 >> /var/log/check_clusternas.log
                #umount -l /rootfs
                #echo $DATE /rootfs unmounted >> /var/log/check_clusternas.log
                mount -t gfs2 /dev/mapper/root_vg01-lv01 /rootfs
                echo $DATE clusternas01 mounted >> /var/log/check_clusternas.log
                exit 0
        fi


        exit 0


else


        if [ -n "$VAR2" ]; then


                if [ -n "$MOUNT02_ERG" ]; then
                        echo $DATE OK clusternas02 >> /var/log/check_clusternas.log
                        exit 0
                else
                        echo $DATE switch to clusternas02 >> /var/log/check_clusternas.log
                        #umount -l /rootfs
                        #echo $DATE /rootfs unmounted >> /var/log/check_clusternas.log
                        mount -t gfs2 /dev/mapper/root_vg02-lv02 /rootfs
                        echo $DATE clusternas02 mounted >> /var/log/check_clusternas.log
                        exit 0
                fi


        else
                echo $DATE Kein clusternas verfügbar >> /var/log/check_clusternas.log
                exit 0
        fi


        exit 0
fi