diff --git a/install_postfixadmin.sh b/install_postfixadmin.sh
index d1c1dcc..8e0d498 100755
--- a/install_postfixadmin.sh
+++ b/install_postfixadmin.sh
@@ -26,6 +26,7 @@ conf_file="${_src_base_dir}/conf/install_postfixadmin.conf"
 curdir=`pwd`
 
 log_file="$(mktemp)"
+backup_date="$(date +%Y-%m-%d-%H%M)"
 
 declare -A check_entry_main_cf_arr
 
@@ -424,12 +425,30 @@ echo -e "\n\n\t\033[37m\033[1mPre-installion tasks ..\033[m\n"
 # -
 _failed=false
 > $log_file
-echononl "\tCreate Postfix Database '$POSTFIX_DB_NAME'"
-if [ "$POSTFIX_DB_TYPE" = "mysql" ]; then 
-   echo -n " (MySQL).."
+
+if [[ "$POSTFIX_DB_TYPE" = "mysql" ]] ; then
    if ! mysql $mysql_credential_args -N -s -e \
       "SELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA WHERE SCHEMA_NAME = '$POSTFIX_DB_NAME'" 2>> $log_file \
       | grep $POSTFIX_DB_NAME >> $log_file 2>&1 ; then
+      database_exists=false
+   else
+      database_exists=true
+   fi
+elif [[ "$POSTFIX_DB_TYPE" = "pgsql" ]]; then
+   count=$(su - postgres -c "psql -q -A -t -l" | grep -c -e "^$POSTFIX_DB_NAME")
+   if [[ $count -eq 0 ]];then
+      database_exists=false
+   else
+      database_exists=true
+   fi
+else
+   fatal "Cannot detect database type (value of  POSTFIX_DB_TYPE is neither 'mysql' nor 'pgsql')"
+fi
+
+if ! $database_exists ; then
+   echononl "\tCreate Postfix Database '$POSTFIX_DB_NAME'"
+   if [ "$POSTFIX_DB_TYPE" = "mysql" ]; then 
+      echo -n " (MySQL).."
       mysql $mysql_credential_args -N -s -e \
          "CREATE DATABASE IF NOT EXISTS $POSTFIX_DB_NAME CHARACTER SET utf8 COLLATE utf8_general_ci" >> $log_file 2>&1
       if [[ $? -ne 0 ]] ; then
@@ -450,13 +469,8 @@ if [ "$POSTFIX_DB_TYPE" = "mysql" ]; then
       else
          echo_ok
       fi
-   else
-      echo_skipped
-   fi
-elif [ "$POSTFIX_DB_TYPE" = "pgsql" ]; then
-   echo -n " (PostgreSQL).."
-   count=`su - postgres -c "psql -q -A -t -l" | grep -c -e "^$POSTFIX_DB_NAME"`
-   if [ $count -eq 0 ];then
+   elif [ "$POSTFIX_DB_TYPE" = "pgsql" ]; then
+      echo -n " (PostgreSQL).."
       echo "CREATE ROLE $POSTFIX_DB_USER WITH LOGIN NOCREATEDB NOCREATEROLE NOSUPERUSER ENCRYPTED PASSWORD '$POSTFIX_DB_PASS'" \
          | su - postgres -c "psql" >> $log_file 2>&1
       if [[ $? -ne 0 ]] ; then
@@ -472,8 +486,27 @@ elif [ "$POSTFIX_DB_TYPE" = "pgsql" ]; then
       else
          echo_ok
       fi
-   else
-      echo_skipped
+   fi
+else
+   echononl "\tBackup Postfix Database '$POSTFIX_DB_NAME'"
+   if [[ "$POSTFIX_DB_TYPE" = "mysql" ]]; then 
+      echo -n " (MySQL).."
+      mysqldump $mysql_credential_args --opt $POSTFIX_DB_NAME >> ${WEBSITE_BASEDIR}/${POSTFIX_DB_NAME}.${backup_date}.sql 2> $log_file
+      if [[ $? -eq 0 ]]; then
+         echo_ok
+      else
+         echo_failed
+         error "$(cat $log_file)"
+      fi
+   elif [[ "$POSTFIX_DB_TYPE" = "pgsql" ]]; then
+      echo -n " (PostgreSQL).."
+      su - postgres -c "pg_dump $POSTFIX_DB_NAME" >> ${WEBSITE_BASEDIR}/${POSTFIX_DB_NAME}.${backup_date}.sql 2> $log_file
+      if [[ $? -eq 0 ]]; then
+         echo_ok
+      else
+         echo_failed
+         error "$(cat $log_file)"
+      fi
    fi
 fi
 
@@ -571,7 +604,7 @@ fi
 echononl "\tBackup existing source directory 'postfixadmin-${PF_ADMIN_VERSION}'.."
 if [[ -d "${_src_base_dir}/postfixadmin-${PF_ADMIN_VERSION}" ]]; then
    mv ${_src_base_dir}/postfixadmin-${PF_ADMIN_VERSION} \
-      ${_src_base_dir}/postfixadmin-${PF_ADMIN_VERSION}.$(date +%Y%m%d-%H%M)
+      ${_src_base_dir}/postfixadmin-${PF_ADMIN_VERSION}.${backup_date}
    if [[ $? -eq 0 ]]; then
       echo_ok
    else
@@ -607,7 +640,7 @@ fi
 echononl "\tBackup existing web-directory 'postfixadmin-${PF_ADMIN_VERSION}'.."
 if [[ -d "${WEBSITE_BASEDIR}/postfixadmin-${PF_ADMIN_VERSION}" ]]; then
    mv ${WEBSITE_BASEDIR}/postfixadmin-${PF_ADMIN_VERSION} \
-      ${WEBSITE_BASEDIR}/postfixadmin-${PF_ADMIN_VERSION}.`date +%Y%m%d-%H%M` > $log_file 2>&1
+      ${WEBSITE_BASEDIR}/postfixadmin-${PF_ADMIN_VERSION}.${backup_date} > $log_file 2>&1
    if [[ $? -eq 0 ]]; then
        echo_ok
    else
@@ -1349,7 +1382,7 @@ fi
 
 echononl "\tBackup existing script 'vacation.pl'"
 if [[ -f "/var/spool/vacation/vacation.pl" ]] ; then
-   mv /var/spool/vacation/vacation.pl /var/spool/vacation/vacation.pl.$(date +%Y%m%d-%H%M) > "$log_file" 2>&1
+   mv /var/spool/vacation/vacation.pl /var/spool/vacation/vacation.pl.${backup_date} > "$log_file" 2>&1
    if [[ $? -ne 0 ]]; then
       echo_failed
       error "$(cat $log_file)"
@@ -1432,7 +1465,7 @@ fi
 
 echononl "\tBackup existing file '/etc/postfixadmin/vacation.conf'"
 if [[ -f "/etc/postfixadmin/vacation.conf" ]]; then
-   mv /etc/postfixadmin/vacation.conf /etc/postfixadmin/vacation.conf.$(date +%Y%m%d-%H%M) > "$log_file" 2>&1
+   mv /etc/postfixadmin/vacation.conf /etc/postfixadmin/vacation.conf.${backup_date} > "$log_file" 2>&1
    if [[ $? -eq 0 ]];then
       echo_ok
    else
@@ -1985,7 +2018,7 @@ fi
 echononl "\tBackup existing post-deletion script"
 if [[ -f "/usr/local/bin/postfixadmin-mailbox-postdeletion.sh" ]]; then
    mv /usr/local/bin/postfixadmin-mailbox-postdeletion.sh \
-      /usr/local/bin/postfixadmin-mailbox-postdeletion.sh.$(date +%Y%m%d-%H%M) > $log_file 2>&1
+      /usr/local/bin/postfixadmin-mailbox-postdeletion.sh.${backup_date} > $log_file 2>&1
    if [[ $? -eq 0 ]]; then
       echo_ok
    else
@@ -2139,7 +2172,7 @@ fi
 echononl "\tBackup existing post-deletion script"
 if [[ -f "/usr/local/bin/postfixadmin-domain-postdeletion.sh" ]]; then
    mv /usr/local/bin/postfixadmin-domain-postdeletion.sh \
-      /usr/local/bin/postfixadmin-domain-postdeletion.sh.$(date +%Y%m%d-%H%M) > $log_file 2>&1
+      /usr/local/bin/postfixadmin-domain-postdeletion.sh.${backup_date} > $log_file 2>&1
    if [[ $? -eq 0 ]]; then
       echo_ok
    else