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auricom-home-cluster/infrastructure/ansible/roles/truenas/files/scripts/snapshots_clearempty.py
2022-11-20 16:37:40 +01:00

108 lines
4.5 KiB
Python

#!/usr/bin/env python3
# clearempty.py - Koen Vermeer <k.vermeer@eyehospital.nl>
# Inspired by rollup.py by Arno Hautala <arno@alum.wpi.edu>
# modifications by Arno Hautala
# This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.
# (CC BY-SA-3.0) http://creativecommons.org/licenses/by-sa/3.0/
# This script removes empty snapshots, based on their 'used' property.
# Note that one snapshot's 'used' value may change when another snapshot is
# destroyed. This script iteratively destroys the oldest empty snapshot. It
# does not remove the latest snapshot of each dataset or manual snapshots
import subprocess
import argparse
import sys
from collections import defaultdict
parser = argparse.ArgumentParser(description='Removes empty auto snapshots.')
parser.add_argument('datasets', nargs='+', help='the root dataset(s) from which to remove snapshots')
parser.add_argument('--test', '-t', action="store_true", default=False, help='only display the snapshots that would be deleted, without actually deleting them. Note that due to dependencies between snapshots, this may not match what would really happen.')
parser.add_argument('--recursive', '-r', action="store_true", default=False, help='recursively removes snapshots from nested datasets')
parser.add_argument('--prefix', '-p', action='append', help='list of snapshot name prefixes that will be considered')
args = parser.parse_args()
if not args.prefix:
args.prefix = ['auto']
args.prefix = [prefix+"-" for prefix in set(args.prefix)]
deleted = defaultdict(lambda : defaultdict(lambda : defaultdict(int)))
snapshot_was_deleted = True
while snapshot_was_deleted:
snapshot_was_deleted = False
snapshots = defaultdict(lambda : defaultdict(lambda : defaultdict(int)))
# Get properties of all snapshots of the selected datasets
for dataset in args.datasets:
subp = subprocess.Popen(["zfs", "get", "-Hrpo", "name,property,value", "type,creation,used,freenas:state", dataset], stdout=subprocess.PIPE)
zfs_snapshots = subp.communicate()[0]
if subp.returncode:
print("zfs get failed with RC=%s" % subp.returncode)
sys.exit(1)
for snapshot in zfs_snapshots.splitlines():
name,property,value = snapshot.decode().split('\t',3)
# if the rollup isn't recursive, skip any snapshots from child datasets
if not args.recursive and not name.startswith(dataset+"@"):
continue
try:
dataset,snapshot = name.split('@',2)
except ValueError:
continue
snapshots[dataset][snapshot][property] = value
# Ignore non-snapshots and not-auto-snapshots
# Remove already destroyed snapshots
for dataset in list(snapshots.keys()):
latest = None
latestNEW = None
for snapshot in sorted(snapshots[dataset], key=lambda snapshot: snapshots[dataset][snapshot]['creation'], reverse=True):
if not any(map(snapshot.startswith, args.prefix)) \
or snapshots[dataset][snapshot]['type'] != "snapshot":
del snapshots[dataset][snapshot]
continue
if not latest:
latest = snapshot
del snapshots[dataset][snapshot]
continue
if not latestNEW and snapshots[dataset][snapshot]['freenas:state'] == 'NEW':
latestNEW = snapshot
del snapshots[dataset][snapshot]
continue
if snapshots[dataset][snapshot]['freenas:state'] == 'LATEST':
del snapshots[dataset][snapshot]
continue
if snapshots[dataset][snapshot]['used'] != '0' \
or snapshot in list(deleted[dataset].keys()):
del snapshots[dataset][snapshot]
continue
# Stop if no snapshots are in the list
if not snapshots[dataset]:
del snapshots[dataset]
continue
# destroy the most recent empty snapshot
snapshot = max(snapshots[dataset], key=lambda snapshot: snapshots[dataset][snapshot]['creation'])
if not args.test:
# destroy the snapshot
subprocess.call(["zfs", "destroy", dataset+"@"+snapshot])
deleted[dataset][snapshot] = snapshots[dataset][snapshot]
snapshot_was_deleted = True
for dataset in sorted(deleted.keys()):
if not deleted[dataset]:
continue
print(dataset)
for snapshot in sorted(deleted[dataset].keys()):
print("\t", snapshot, deleted[dataset][snapshot]['used'])