cephfs-snp

#!/bin/bash

#
# Script that creates cephfs snapshots, manually or from cron
#
# Usage:
#          sudo cephfs-snp  <dir> (<tag>) (<limit>) (<seconds>) 
#
# Copyleft 2020 by Stefano Marinelli <stefano@dragas.it>
# GPL licensed (see end of file) * Use at your own risk!
#
# Based on btrfs-snp by Ignacio Nunez Hernanz 
#
# Based on btrfs-snap by Birger Monsen
#

function cephfs-snp()
{
  local   BIN="${0##*/}"
  local   DIR="${1}"
  local   TAG="${2:-snapshot}"
  local LIMIT="${3:-0}"
  local  TIME="${4:-0}"
  local   DST="${1:-.snap}"

  ## usage
  [[ "$*" == "" ]] || [[ "$1" == "-h" ]] || [[ "$1" == "--help" ]] && {
    echo "Usage: $BIN <dir> (<tag>) (<limit>) (<seconds>) (<destdir>)

  dir     │ create snapshot of <dir>
  tag     │ name the snapshot <tag>_<timestamp>
  limit   │ keep <limit> snapshots with this tag. 0 to disable
  seconds │ don't create snapshots before <seconds> have passed from last with this tag. 0 to disable

Cron example: Hourly snapshot for one day, daily for one week, weekly for one month, and monthly for one year.

cat > /etc/cron.hourly/$BIN <<EOF
#!/bin/bash
/usr/local/sbin/$BIN /home hourly  24 3600
/usr/local/sbin/$BIN /home daily    7 86400
/usr/local/sbin/$BIN /home weekly   4 604800
/usr/local/sbin/$BIN /     weekly   4 604800
/usr/local/sbin/$BIN /home monthly 12 2592000
EOF
chmod +x /etc/cron.hourly/$BIN"
    return 0
  }

  ## checks
  local SNAPSHOT=${TAG}_$( date +%F_%H%M%S )

  [[ ${EUID} -ne 0  ]] && { echo "Must be run as root. Try 'sudo $BIN'"; return 1; }
  [[ -d "$SNAPSHOT" ]] && { echo "$SNAPSHOT already exists"            ; return 1; }

  local SNAPS=( $( ls -d "$DST/.snap/${TAG}_"* 2>/dev/null ) )

  ## check time of the last snapshot for this tag
  [[ "$TIME" != 0 ]] && [[ "${#SNAPS[@]}" != 0 ]] && {
    local LATEST=$( sed -r "s|.*_(.*_.*)|\\1|;s|_([0-9]{2})([0-9]{2})([0-9]{2})| \\1:\\2:\\3|" <<< "${SNAPS[-1]}" )
    LATEST=$( date +%s -d "$LATEST" ) || return 1

    [[ $(( LATEST + TIME )) -gt $( date +%s ) ]] && { echo "No new snapshot needed for $TAG"; return 0; }
  }

  ## do it
  mkdir  "$DIR/.snap/$SNAPSHOT" || return 1

  ## prune older backups
  [[ "$LIMIT" != 0 ]] && \
  [[ ${#SNAPS[@]} -ge $LIMIT ]] && \
    echo "Pruning old snapshots..." && \
    for (( i=0; i <= $(( ${#SNAPS[@]} - LIMIT )); i++ )); do
      echo Delete "${SNAPS[$i]}"
      rmdir "${SNAPS[$i]}"
    done

  echo "snapshot $SNAPSHOT generated"
}

cephfs-snp "$@"

# License
#
# This script is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This script is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this script; if not, write to the
# Free Software Foundation, Inc., 59 Temple Place, Suite 330,
# Boston, MA  02111-1307  USA