#!/bin/sh
# mk_snapshot.sh

# ------------- system commands used by this script --------------------
HOST=`hostname`
. /home/bin/$HOST/snapshot.data

ID=id
ECHO=echo
MOUNT=/bin/mount
RM=rm
MV=mv
CP=cp
TOUCH=/bin/touch
HOST=`hostname`
DATE=/bin/date
SET=set

RSYNC=/usr/bin/rsync


# ------------- file locations -----------------------------------------

if [ -z "$MOUNT_DEVICE" ] ; then
	echo "MOUNT_DEVICE not defined"
	exit 1
fi

if [ -z "$SNAPSHOT_RW" ] ; then
	echo "SNAPSHOT_RW not defined"
	exit 1
fi

if [ ! -f "$EXCLUDES" ] ; then
	echo "Excluding file $EXCLUDES not found"
	exit 1
fi

if [ ! -d "$DIR_TO_SAVE" ] ; then
	echo "DIR_TO_SAVE not found"
	exit 1
fi

if [ -z "$DIR_HOURLY" ] ; then
	echo "DIR_HOURLY not defined"
	exit 1
fi

# ------------- the script itself --------------------------------------

# make sure we're running as root
if [ `$ID -u` != 0 ] ; then
	$ECHO "Sorry, must be root.  Exiting..."
	exit
fi

# attempt to remount the RW mount point as RW; else abort
$MOUNT -o remount,rw $MOUNT_DEVICE $SNAPSHOT_RW 
if [ $? != 0 ] ; then
        $ECHO "snapshot: could not remount $SNAPSHOT_RW readwrite"
        exit
fi


# rotating snapshots of $DIR_TO_SAVE

# step 1: delete the oldest snapshot, if it exists:
if [ -d $SNAPSHOT_RW$DIR_TO_SAVE/$DIR_HOURLY.3 ] ; then 
	$RM -rf $SNAPSHOT_RW$DIR_TO_SAVE/$DIR_HOURLY.3
fi

# step 2: shift the middle snapshots(s) back by one, if they exist
if [ -d $SNAPSHOT_RW$DIR_TO_SAVE/$DIR_HOURLY.2 ] ; then
	$MV $SNAPSHOT_RW$DIR_TO_SAVE/$DIR_HOURLY.2 $SNAPSHOT_RW$DIR_TO_SAVE/$DIR_HOURLY.3
fi
if [ -d $SNAPSHOT_RW$DIR_TO_SAVE/$DIR_HOURLY.1 ] ; then
	$MV $SNAPSHOT_RW$DIR_TO_SAVE/$DIR_HOURLY.1 $SNAPSHOT_RW$DIR_TO_SAVE/$DIR_HOURLY.2
fi

# step 3: make a hard-link-only (except for dirs) copy of the latest snapshot,
# if that exists
if [ -d $SNAPSHOT_RW$DIR_TO_SAVE/$DIR_HOURLY.0 ] ; then
	$CP -al $SNAPSHOT_RW$DIR_TO_SAVE/$DIR_HOURLY.0 $SNAPSHOT_RW$DIR_TO_SAVE/$DIR_HOURLY.1
fi

# step 4: rsync from the system into the latest snapshot (notice that
# rsync behaves like cp --remove-destination by default, so the destination
# is unlinked first.  If it were not so, this would copy over the other
# snapshot(s) too!
$DATE "+%Y.%m.%d/%T mk_snapshot.sh:"
$RSYNC -a --delete --delete-excluded  \
        --exclude-from="$EXCLUDES" \
        $DIR_TO_SAVE/ $SNAPSHOT_RW$DIR_TO_SAVE/$DIR_HOURLY.0

# step 5: update the mtime of $DIR_HOURLY.0 to reflect the snapshot time
$TOUCH $SNAPSHOT_RW$DIR_TO_SAVE/$DIR_HOURLY.0

# and thats it for home.

# now remount the RW snapshot mountpoint as readonly

$MOUNT -o remount,ro $MOUNT_DEVICE $SNAPSHOT_RW
if [ $? != 0 ] ; then
        $ECHO "snapshot: could not remount $SNAPSHOT_RW readonly"
        exit
fi
:code:
Das Script kommt auf vielen Rechnern zum Einsatz, daher sind die rechnerspezifischen Daten ausgelagert:
:code:(sh)
#!/bin/sh
#/home/bin/rex/snapshot.data

MOUNT_DEVICE=/dev/sda21
SNAPSHOT_RW=/sicherung
EXCLUDES=/home/bin/rex/snapshot_exclude.lst
DIR_TO_SAVE=/home
DIR_HOURLY=sicherung

1 */4  *  *  *  /home/bin/std/mk_snapshot.sh >>/var/log/rex/snapshot.log

#! /bin/sh
# Aufruf: snapshot_rotate.sh [ day week month ]
#

ID=id
ECHO=echo

MOUNT=/bin/mount
RM=rm
MV=mv
CP=cp
TOUCH=/bin/touch
HOST=`hostname`
DATE=/bin/date
SET=set

# make sure we're running as root
if [ `$ID -u` != 0 ] ; then
        $ECHO "Sorry, must be root.  Exiting..."
        exit 1
fi


source /home/bin/$HOST/snapshot.data
if [ -z "$MOUNT_DEVICE" ] ; then
	$ECHO "MOUNT_DEVICE not defined"
        exit 1
fi

if [ -z "$SNAPSHOT_RW" ] ; then
        $ECHO "SNAPSHOT_RW not defined"
        exit 1
fi
if [ -z "$DIR_TO_SAVE" ] ; then
        $ECHO "DIR_TO_SAVE not defined"
        exit 1
fi
if [ -z "$DIR_HOURLY" ] ; then
        $ECHO "DIR_HOURLY not defined"
        exit 1
fi


MODE=$1
if [ -z "$MODE" ] ; then
	MODE=day
fi
case  "$MODE" in
	day)
		TARGET=`$DATE "+%A"`
		break;;
	week)
		TARGET=`$DATE "+woche_%V"`
		break;;
	month)
		TARGET=`$DATE "+%b"`
		break;;
	
	*)
 		$ECHO "unknown mode (instead of:  day week month)"
		exit 1
esac

# attempt to remount the RW mount point as RW; else abort
$MOUNT -o remount,rw $MOUNT_DEVICE $SNAPSHOT_RW
if [ $? != 0 ] ; then
        $ECHO "snapshot: could not remount $SNAPSHOT_RW readwrite"
        exit
fi
SOURCE=$SNAPSHOT_RW$DIR_TO_SAVE/$DIR_HOURLY.0
if [ ! -d $SOURCE ] ; then
	SOURCE=$SNAPSHOT_RW$DIR_TO_SAVE/$DIR_HOURLY.1
fi
if [ ! -d $SOURCE ] ; then
	SOURCE=$SNAPSHOT_RW$DIR_TO_SAVE/$DIR_HOURLY.2
fi
if [ ! -d $SOURCE ] ; then
	SOURCE=$SNAPSHOT_RW$DIR_TO_SAVE/$DIR_HOURLY.3
fi
if [ ! -d $SOURCE ] ; then
	$ECHO "no source available! $SOURCE"
	exit 2
fi
$DATE "+%Y.%m.%d/%T: snapshot_rotate.sh $MODE"
TRG=$SNAPSHOT_RW$DIR_TO_SAVE/$TARGET
$SET -x
if [ -d $TRG ] ; then
	$RM -fR $TRG
fi
$CP -al $SOURCE $TRG
$SET +x
# attempt to remount the RW mount point as RW; else abort
$MOUNT -o remount,ro $MOUNT_DEVICE $SNAPSHOT_RW
if [ $? != 0 ] ; then
        $ECHO "snapshot: could not remount $SNAPSHOT_RW readonly"
        exit
fi

1 30 vlinux.backup.day  nice -n -9 /home/bin/std/snapshot_rotate.sh day >>/var/log/rex/snapshot.log
7 60 vlinux.backup.week  nice -n -9 /home/bin/std/snapshot_rotate.sh week >>/var/log/rex/snapshot.log