A replication script for ZFS

replicate.bash

#!/usr/bin/env bash
# coding: utf-8
# A replication script for ZFS
# by Akihiro Uchida, CC0 dedicated to the public domain
# see http://creativecommons.org/publicdomain/zero/1.0/
usage="usage: $(basename $0) [-v] src dst"

die() {
    echo "$@" >&2
    exit 1
}

while getopts ":v" opt; do
    case $opt in
        v) set -v;;
        *) die $usage;;
    esac
done
shift $((OPTIND - 1))

if [ $# -ne 2 ]; then
    die $usage
fi
src=$1
dst=$2

for filesystem in $src $dst; do
    pool=$(echo $filesystem | cut -d/ -f1)
    if [ -z "$(zpool list $pool 2>/dev/null)" ]; then
        die "zfs pool $pool does not exist!"
    fi
    mntpt=$(zfs get -H mountpoint $pool | cut -f3)
    path=$(echo $filesystem | sed -e "s|$pool|$mntpt|")
    if ! [ -e "$path" ]; then
        die "path to $filesystem: $path does not exist!"
    fi
done

src_snaps=$(zfs list -H -t snapshot | grep "$src" | cut -f1 | cut -d@ -f2)
dst_snaps=$(zfs list -H -t snapshot | grep "$dst" | cut -f1 | cut -d@ -f2)
last_common=$(sort <(echo "$src_snaps") <(echo "$dst_snaps") | uniq -d | tail -1)

present=$(date +"%Y%m%d-%H:%M")
zfs snapshot $src@$present

if [ -z "$lastcommon" ]; then
    zfs send $src@$present | zfs recv -F $dst || die
else
    zfs rollback $dst@$last_common || die
    zfs send -i $src@$last_common $src@$present | zfs recv $dst || die
    zfs release keep $src@$last_common
    zfs release keep $dst@$last_common
fi
zfs hold keep $src@$present
zfs hold keep $dst@$present
exit 0