This backup script uses btrfs for snapshots and delete oldest snapshots when we reach a certain level of disk usage. Note: The most important difference with tools like rsnapshot is that it can calculate differences at a block level (whereas hardlinks only allow such a thing at a file level). Putting the snapshotting logic on the filesystem laye…

backup-servers.sh

#!/bin/sh -x

# === ARGUMENTS PARSING ===

# We don't want to define a default period
PERIOD=

while echo $1 | grep ^- > /dev/null; do

    if [ "$1" = "--daily" ]; then
	PERIOD=daily
    fi

    if [ "$1" = "--monthly" ]; then
	PERIOD=monthly
    fi

    if [ "$1" = "--period" ]; then
        PERIOD=$2
	shift	
    fi

    shift
done

LOCK=/var/run/backup-servers-$PERIOD.lock

if [ "${PERIOD}" = "" ]; then
	echo "You have to define a period  with the --period arg !" >&2
	exit 1
fi

if [ -f $LOCK ]; then
	PID=`cat $LOCK`
	echo "Other backup locked by process $PID"
	kill -s 0 $PID
	rc=$?
	if [ "$rc" = "0" ] ; then
		echo "Other backup running, stopping right here..."
		exit 1
	else
		echo "Other backup stalled, we can continue"
	fi
fi

echo $$ >$LOCK

# === END OF ARGUMENTS PARSING ===

# === PARAMETERS ===

# * Device we will use
DISK=/mnt/fs5

# * Subvolume used for the backup
SUBVOLUME=${DISK}/servers

# * Current date (you could limit the date to +%Y-%m-%d)
DATE=`/bin/date +%Y-%m-%d_%H-%M-%S`

# * snapshot directory that will be used
SNAPDIR=${DISK}/snap/servers

# * snapshot volume that will be used
SNAPVOL=${SNAPDIR}/${PERIOD}-${DATE}

# * max days to keep daily backups
MAX_DAYLY=60

# * max days to keep monthly backups
MAX_MONTHLY=365

# * Alert limit
LIMIT_ALERT=95

# * High limit
LIMIT_HIGH=90

# * Low limit
LIMIT_LOW=85

# === END OF PARAMETERS ===

# We get the space used over the total allocated space and the total percentage use.
# This is NOT the device total size but it's a lot more reliable than "df -h"
# DISK_USED=`/sbin/btrfs filesystem df ${DISK}|grep Data|grep -Po "used=([0-9]*)"|cut -d= -f2`
# DISK_TOTAL=`/sbin/btrfs filesystem df ${DISK}|grep Data|grep -Po "total=([0-9]*)"|cut -d= -f2`
# DISK_PERC=`echo 100*${DISK_USED}/${DISK_TOTAL}|bc`
DISK_PERC=`df ${DISK} |grep -E -o "([0-9]+)\%"|cut -d% -f1`

#echo DISK_PERC=${DISK_PERC}

mount -a

# We create the snapshot dir if it doesn't exist
if [ ! -d ${SNAPDIR} ]; then
	mkdir -p ${SNAPDIR}
fi

cd ${SNAPDIR}

# If we are over the low free space limit,
# we delete two days of daily backup.
if [ $DISK_PERC -gt $LIMIT_LOW ]; then
        echo "LOW LIMIT reached: $DISK_PERC > $LIMIT_LOW : Deleting 2 days" >&2

        OLDEST_FILES=`ls --sort=time -r|grep "daily-.*"|head -2`
        for file in $OLDEST_FILES; do
                /sbin/btrfs subvolume delete $file;
        done

fi

# If we are over the high free space limit,
# we delete a month of monthly backup
if [ $DISK_PERC -gt $LIMIT_HIGH ]; then
        echo "HIGH LIMIT reached: $DISK_PERC > $LIMIT_HIGH : Deleting 1 month" >&2

        OLDEST_FILES=`ls --sort=time -r|grep "monthly-.*"|head -1`
        for file in $OLDEST_FILES; do
                /sbin/btrfs subvolume delete $file;
        done

fi

# If we are over the alert free space limit,
# we delete the first two oldest files we can find
if [ $DISK_PERC -gt $LIMIT_ALERT ]; then
        echo "ALERT LIMIT reached: $DISK_PERC > $LIMIT_ALERT : Deleting the 2 oldest" >&2

        OLDEST_FILES=`ls --sort=time -r|head -2`
        for file in $OLDEST_FILES; do
                /sbin/btrfs subvolume delete $file;
        done
fi


# We touch the subvolume to change the modification date 
touch ${SUBVOLUME}

# We do a snapshot of the subvolume
if [ ! -d "${SNAPVOL}" ]; then
	/sbin/btrfs subvolume snapshot ${SUBVOLUME} ${SNAPVOL}
fi

# We delete the backups older than MAX_DAYLY
find ${SNAPDIR} -mindepth 1 -maxdepth 1 -mtime +${MAX_DAYLY} -name "daily-*" -exec /sbin/btrfs subvolume delete {} \;

# We delete the backups older than MAX_MONTHLY
find ${SNAPDIR} -mindepth 1 -maxdepth 1 -mtime +${MAX_MONTHLY} -name "monthly-*" -exec /sbin/btrfs subvolume delete {} \;


# This is the actual backup code
# You need to save your data into the ${SUBVOLUME} directory

# We will only do this backup for the daily task
if [ "${PERIOD}" = "daily" ]; then

RSYNC_ARGS="-auvz --delete --partial --partial-dir=.part --exclude /proc --exclude /sys --exclude /dev --exclude swapfile --exclude /home/nginx --exclude /home/var_lib_php5"
RSYNC_POST="grep -v vanished"
date
echo "=== OVH1 ==="
rsync ${RSYNC_ARGS} --password-file=/etc/rsync.pass.ovh1 rsync://[email protected]/root ${SUBVOLUME}/ovh1 | ${RSYNC_POST}
#rsync ${RSYNC_ARGS} --password-file=/etc/rsync.pass.ovh2 rsync://[email protected]/root ${SUBVOLUME}/ovh2 | ${RSYNC_POST}
date
echo "=== OVH3 ==="
rsync ${RSYNC_ARGS} --password-file=/etc/rsync.pass.ovh3 rsync://[email protected]/root ${SUBVOLUME}/ovh3 | ${RSYNC_POST}
date
echo "=== LOCALHOST ==="
rsync ${RSYNC_ARGS} /etc ${SUBVOLUME}/localhost | ${RSYNC_POST}
date
rsync ${RSYNC_ARGS} / --exclude /mnt ${SUBVOLUME}/localhost/ | ${RSYNC_POST}
date
fi

rm $LOCK