add tool to make and upload backups from ZFS snaps

zfsbk.sh

@@ -0,0 +1,116 @@
+#! /bin/sh
+
+# make a backup collection having 1 full and N-1 incremental backups.
+# set to 1 to avoid incrementals and always take full dumps.
+max_incremental=4
+zpool="zroot"
+destination_store="u84693@u84693.your-backup.de:calaf/"
+
+usage () {
+    echo "Usage:"
+    echo "zfsbk.sh <bkname> [numincr]"
+    echo "Takes & sends backup with given name. If snapshots with"
+    echo "this name exist, backup incrementally. Limit incremental"
+    echo "backup sequences to 'numincr' steps (default 1 = alw. full)."
+    echo
+    echo "Optional envvars:"
+    echo "UPLOAD_PATH   upload generated backup to this path. scp:// or rsync://"
+}
+
+# first argument: name of backup set
+if [ $# -lt 1 ]
+then
+    usage
+    exit 1
+fi
+
+bkname=$1
+if ! echo $bkname | grep -qiE '^[a-z0-9-]+$'
+then
+    echo "Given bkname is invalid. Want alphanumeric and hyphens."
+    exit 1
+fi
+if echo "$2" | grep -qE '^[1-9][0-9]*$'
+then
+    max_incremental=$2
+fi
+
+export PATH=$PATH:/usr/local/bin
+
+# list snapshots by decreasing time. Arguments: [name] restrict listing to this tag
+list_named_snaps () {
+    local bkname=$1
+    snapdir="/.zfs/snapshot"
+    for i in $snapdir/zbk-$bkname-*
+    do
+        test -e "$i" && (echo $i |sed "s@^$snapdir/@@")
+    done | sort -r
+}
+
+# remove all datasets for a given tag. Arguments: $1 -> bkname
+reset_sequence () {
+    local bkname=$1
+    list_named_snaps $bkname | while read snapname
+    do
+        zfs destroy -r $zpool@$snapname
+    done
+}
+
+# take snapshot
+#echo ./zfssnap.sh $bkname $max_incremental
+if ! ./zfssnap.sh $bkname $max_incremental
+then
+    echo "Error creating snapshot! Code $?"
+    exit 1
+fi
+
+# get label
+num_snaps=`list_named_snaps $bkname | awk 'END {print NR}'`
+label_latest=`list_named_snaps $bkname | awk NR==1`
+
+# decide what to do based on how many snapshots were found
+if [ $num_snaps -eq 0 ]
+then
+    # no snapshots. Something's wrong
+    echo "Error, no snapshots found for $bkname!"
+    list_named_snaps $bkname
+    exit 1
+elif [ $num_snaps -eq 1 ]
+then
+    # first snapshot. Send full
+    bkfile="/backups/${label_latest}.dump"
+    #echo zfs send -R $zpool@$label_latest
+    zfs send -R $zpool@$label_latest 2>/dev/null > $bkfile
+else
+    # n-th snapshot. Send incrementally
+    label_2ndlatest=`list_named_snaps $bkname | awk NR==2`
+    bkfile="/backups/${label_latest}--${label_2ndlatest}.dump"
+    #echo zfs send -i $label_2ndlatest -R $zpool@$label_latest
+    zfs send -i $label_2ndlatest -R $zpool@$label_latest 2>/dev/null > $bkfile
+fi
+
+if [ $num_snaps -eq $max_incremental ]
+then
+    # finished the incremental sequence. Take full backup next time
+    echo "Sequence of $max_incremental increm steps complete. Resetting."
+    reset_sequence $bkname
+fi
+
+
+# upload backup to remote location
+if [ "x$UPLOAD_PATH" != x ]
+then
+    #echo "Archiving $bkfile remotely..."
+    if echo "$UPLOAD_PATH" | grep -qE '^rsync://'
+    then
+        rsync -qz $bkfile ${UPLOAD_PATH#rsync://}
+    elif echo "$UPLOAD_PATH" | grep -qE '^scp://'
+    then
+        scp -BCq $bkfile ${UPLOAD_PATH#scp://}
+    else
+        echo "UPLOAD_PATH not understood! '$UPLOAD_PATH'"
+        echo "Expecting rsync://.. or scp://.."
+        exit 1
+    fi
+fi
+