usb-backup

#!/bin/bash
# by non7top
LC_ALL=C
LANG=C

EMAIL=""
RETENTION=10
SOURCE=/backups/fusion
DEST=/mnt/backups
USB_LABEL="backups"
EXCLUDE="--exclude=DEV"

LOG_FILE=/var/tmp/usb-backup-$(date +"%F_%H-%M-%S").log

__exit() {
	mail -s "$STATUS - [usb-backup] - `date`" $EMAIL < $LOG_FILE
	:
}

__log() { echo ">> `date` :: $*" ; }

exec > $LOG_FILE 2>&1
WEEK="$(( $(date +%W )%2 ))"

# run on odd weeks only, i.e. every second week
if [ $WEEK -eq 0 ]; then
	__log "Skipping script run on even week: $WEEK"
	__log "Exit"
	exit 0
fi

trap __exit EXIT

__log  "Backup to usb started"

k=$( df -hP $DEST | tail -n1|awk '{print $6}' )
if [ "x$k" != "x$DEST" ]; then
	mount LABEL=$USB_LABEL /mnt/backups || { __log "Unable to mount usb drive"; STATUS="Failed"; exit 1; }
fi

D="$DEST/fusion_$(date +%F)"
STATUS="Success"

__check_space () {
	NEED=$( du -smc $EXCLUDE $SOURCE/* |grep total|awk '{print $1}' )
	AVAIL=$( df -mP /mnt/backups/|tail -n1 |awk '{print $4}' )
	if [ $AVAIL -lt $NEED ]; then
		__log "No enough space in destination - need: ${NEED}MB have: ${AVAIL}MB"
		return 1
	fi
}

__check_space
if [ $? -eq 1 ]; then
	# Delete 1 latest backup
	B=$( ls -1d /mnt/backups/fusion_*|sort -n|head -n1 )
	__log "No enough space so delete one latest backup: $B"
fi

__check_space
if [ $? -eq 1 ]; then
	# Error out
	__log "No enough space after cleanup, manual intervention required"
	STATUS="Failed";
	exit 1
fi

__log "Starting rsync"
rsync --stats -aHS $EXCLUDE $SOURCE/ $D/
res=$?
__log "Finished rsync with return code: $res"


__delete_old() {
	O=$( ls -1d $DEST/fusion_*|sort -nr|awk "NR >$RETENTION" )
	__log "Deleting old backups with retention $RETENTION: "
	echo "$O"
	__log "Remaining backups:"
	ls -ld $DEST/fusion_*
}

if [ $res -eq 0 ]; then
	__delete_old
else
	STATUS="Warning"
	__log "Not purging old backups since rsync completed with error"
fi

__log "Unmounting usb drive"
umount /mnt/backups	
__log "Backup complete"