1 #!/bin/sh

     2 

     3 SNAPSIZE='500M'

     4 

     5 warn() {

     6     echo $@ >&2

     7 }

     8 

     9 die() {

    10     if [ $# -ne 0 ]; then

    11 	echo $@ >&2

    12     else

    13 	echo something went wrong

    14     fi

    15     exit -1

    16 }

    17 

    18 usage() {

    19 

    20 cat <<__U

    21 usage:

    22  $0 [-s snapsize] /dev/<vgname>/<lvname>

    23  or

    24  $0 [-s snapsize] <vgname>/<lvname>

    25  but not (yet?)

    26  $0 [-s snapsize] /dev/mapper/<vgname>-<lvname>

    27 __U

    28 

    29 exit -1

    30 

    31 }

    32 

    33 while getopts "s:" opt; do

    34   case $opt in

    35     s)

    36       SNAPSIZE="$OPTARG"

    37       ;;

    38     \?)

    39       usage

    40       ;;

    41   esac

    42 done

    43 shift $((OPTIND-1))

    44 

    45 p=${1:?device required}

    46 p=${p#/dev/}

    47 vg=${p%/*}

    48 lv=${p##*/}

    49 lvs="snap.${lv}"

    50 

    51 [ -n "${vg}" -a -n "${lv}" -a "${vg}" != "${p}" -a "${lv}" != "${p}" ] || usage

    52 

    53 d=$(date +%Y%m%d%H%M%S)

    54 lvcreate -n"$lvs" -L"$SNAPSIZE" -s "$vg/$lv" || die

    55 if e2fsck -fp "/dev/$vg/$lvs"; then

    56     tune2fs -C 1 -T "$d" "/dev/$vg/$lv" || die

    57     waittime=1 # second

    58     tries=60

    59     i=1

    60     # if you have problems removing volumes then you may have the 'udisks'

    61     # package installed; see:

    62     # http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=549691#74

    63     # https://bugzilla.redhat.com/show_bug.cgi?id=577798#c5

    64     # https://www.redhat.com/archives/linux-lvm/2010-August/msg00029.html

    65     lvremove -f "$vg/$lvs" || die

    66 else

    67     die fsck returned nonzero: this may indicate filesystem corruption on the origin volume. The snapshot has not been removed.

    68 fi