svn commit: r227815 - user/des/zfs-backup

[Dag-Erling Smorgrav]

Author: des
Date: Tue Nov 22 12:12:01 2011
New Revision: 227815
URL: http://svn.freebsd.org/changeset/base/227815

Log:
  Shell script for performing zfs-to-zfs backups.

Added:
  user/des/zfs-backup/
  user/des/zfs-backup/zfs-backup.sh   (contents, props changed)

Added: user/des/zfs-backup/zfs-backup.sh
==============================================================================
--- /dev/null	00:00:00 1970	(empty, because file is newly added)
+++ user/des/zfs-backup/zfs-backup.sh	Tue Nov 22 12:12:01 2011	(r227815)
@@ -0,0 +1,111 @@
+#!/bin/sh
+#-
+# Copyright (c) 2011 Dag-Erling Smørgrav
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer
+#    in this position and unchanged.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+# $Id$
+#
+
+PATH=/usr/bin:/usr/sbin:/bin:/sbin
+
+error() {
+	echo "$@" >/dev/stderr
+	exit 1
+}
+
+info() {
+	echo "$@" | fmt -s -w $((${COLUMNS:-80} - 6))
+}
+
+# Lock
+if [ -z "$SYNC_LOCKED" ] ; then
+	exec lockf -k -s -t0 "$0" env SYNC_LOCKED=$$ "$0" "$@"
+	exit 1
+fi
+
+if [ $# -ne 2 ] ; then
+	error "usage: $0 src dst"
+fi
+src="$1"
+dst="$2"
+
+# Check src / dst datasets
+if ! zfs list "$src" >/dev/null 2>&1 ; then
+	error "'$src' is not a valid dataset"
+fi
+if ! zfs list "$dst" >/dev/null 2>&1 ; then
+	error "'$dst' is not a valid dataset"
+fi
+if [ "$src" = "$dst" ] ; then
+	error "source and destination must be different datasets"
+fi
+if [ "${src#$dst/}" != "$src" -o "${dst#$src/}" != "$dst" ] ; then
+	error "source and destination must be non-overlapping datasets"
+fi
+case src in
+*/*)
+	sub="/${src#*/}"
+	;;
+esac
+
+if tty >/dev/null ; then
+	verbose="-v"
+fi
+
+now=$(date +%Y%m%d-%H%M%S)
+beg=$(date +%s)
+this="bak-$now"
+last=$(zfs list -t snapshot | cut -d' ' -f1 | grep "^$dst$sub at bak-" | sort | tail -1)
+if [ -z "$last" ] ; then
+	# First time
+	info "It looks like this is the first backup from $src to $dst." \
+	    "Continuing will DESTROY the contents of $dst, including any" \
+	    "preexisting snapshots, and replace them with the contents of $src."
+	while :; do
+		echo -n "Are you sure you want to proceed? (yes/no) "
+		read answer
+		case $answer in
+		[Yy][Ee][Ss])
+			break
+			;;
+		[Nn][Oo])
+			exit 1
+			;;
+		esac
+	done
+	zfs snapshot -r "$src@$this" || error "snapshot failed"
+	zfs send $verbose -R "$src@$this" |
+		zfs receive $verbose -F -d -u "$dst"
+else
+	# Subsequent times
+	last="${last#*@}"
+	zfs list "$src@$last" >/dev/null || error "failed to determine last backup"
+	zfs snapshot -r "$src@$this" || error "snapshot failed"
+	zfs send $verbose -R -I "$src@$last" "$src@$this" |
+		zfs receive $verbose -F -d -u "$dst"
+	zfs destroy -r "$src@$last"
+fi
+end=$(date +%s)
+info "Backup from $src to $dst completed in $((end - beg)) seconds"