#!/bin/sh -e

# Based on: http://www.cuddletech.com/blog/pivot/entry.php?id=989

#

# This script differs from original Zynk that uses -R and destination dataset,

# not filesystem.

#

## ZYNK: The Zuper Zimple ZFS Sync (Replication) Tool

## Form: zynk local/dataset root@remote.host destination/dataset

# Please note: The reason this is so simple is because there is no error

# checking, reporting, or cleanup.

#

# In the event that something goes wonkey, you'll manually need to fix the

# snapshots and modify or remove the run datafile which contains the most

# recent snapshot name.

#

# Furthermore, this absolutely relies on the GNU version of 'date' in order to

# get epoch time.

#

# Before using, make sure you've:

#   1. distributed your SSH key to the remote host and can ssh without

#      password;

#   2. delegated zfs rights to the user performing zynk.

#

if [ -z "$3" ]; then

        echo "Usage: zynk local/dataset remote.host destination/dataset"

        exit 1

fi

DATE=`date +%s`

if [ "$DATE" = "%s" ]; then

        echo "Must use GNU Date, please install and modify script."

        exit 2

fi

LOCALFS=$1

HOST=$2

REMOTEFS=$3

RUNF=`echo $LOCALFS-$HOST-$REMOTEFS|sed -e 's{[@/]{-{g'`

CUR=`date '+%F-%H%M'`

TYPE="Full"

SEND_OPTS=""

if [ -e $RUNF ]; then

	TYPE="Incremental"

	SEND_OPTS="-i $LOCALFS@`cat $RUNF`"

fi

echo "$TYPE started at `date`"

zfs snapshot -r $LOCALFS@$CUR

zfs send -v -R $SEND_OPTS $LOCALFS@$CUR | ssh $HOST zfs recv -F -d $REMOTEFS

echo $CUR > $RUNF

echo "$TYPE complete at `date`"