backupberg/04-snapshots-are-easy-and-fun.txt at master · dback/backupberg · GitHub

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enabling snapshots on ZFS
this one is easy-peasy


[root@backupberg2 ~]# DATE=`date +%Y%m%d-%H%M-%s`
[root@backupberg2 ~]# echo $DATE
20170907-1655-1504817734
[root@backupberg2 ~]# zfs snapshot pool60/backups@$DATE
[root@backupberg2 ~]# zfs list -t snapshot
NAME                                      USED  AVAIL  REFER  MOUNTPOINT
pool60/backups@20170907-1647-1504817262      0      -   166T  -
[root@backupberg2 ~]# zfs list -r -t snapshot -o name,creation pool60/backups
NAME                                     CREATION
pool60/backups@20170907-1647-1504817262  Thu Sep  7 16:52 2017

automatic daily snapshots on ZFS
This runs automatically out of cron.


22 2 * * * /usr/local/bin/snapshot_milgram_volume.sh
[root@backupberg2 ~]# cat /usr/local/bin/snapshot_milgram_volume.sh
#!/bin/bash

# David Backeberg
# snapshot the ZFS, probably daily

declare DATE=`date +%Y%m%d-%H%M-%s`

#/usr/sbin/zfs snapshot pool60/backups@$DATE
/usr/sbin/zfs snapshot pool60/gpfs@$DATE
/usr/sbin/zfs snapshot pool60/nexsan@$DATE

/usr/sbin/zfs list -r -t snapshot -o name,creation pool60/backups
/usr/sbin/zfs list -r -t snapshot -o name,creation pool60/gpfs
/usr/sbin/zfs list -r -t snapshot -o name,creation pool60/nexsan

/usr/sbin/zfs list -t snapshot

list existing snapshots

[root@backupberg2 ~]# /usr/sbin/zfs list -r -t snapshot -o name,creation pool60/gpfs
NAME                                  CREATION
pool60/gpfs@20170928-1233-1506616424  Thu Sep 28 12:34 2017
pool60/gpfs@20171104-0222-1509776521  Sat Nov  4  2:22 2017
pool60/gpfs@20171105-0222-1509866521  Sun Nov  5  2:22 2017
pool60/gpfs@20171106-0222-1509952921  Mon Nov  6  2:22 2017
pool60/gpfs@20171107-0222-1510039321  Tue Nov  7  2:22 2017
pool60/gpfs@20171108-0222-1510125721  Wed Nov  8  2:22 2017
[root@backupberg2 ~]# /usr/sbin/zfs list -r -t snapshot -o name,creation pool60/nexsan
NAME                                    CREATION
pool60/nexsan@20170928-1233-1506616424  Thu Sep 28 12:34 2017
pool60/nexsan@20171104-0222-1509776521  Sat Nov  4  2:22 2017
pool60/nexsan@20171105-0222-1509866521  Sun Nov  5  2:22 2017
pool60/nexsan@20171106-0222-1509952921  Mon Nov  6  2:22 2017
pool60/nexsan@20171107-0222-1510039321  Tue Nov  7  2:22 2017
pool60/nexsan@20171108-0222-1510125721  Wed Nov  8  2:22 2017

delete specific snapshots

[root@backupberg2 holmes]# zfs destroy pool60/backups@20170928-1233-1506616424

You need to give the entire path to delete a snapshot. Warning. This is NOT instantaneous. If the snapshot is fairly large, it could take hours for the filesystem to reclaim the filesystem usage, and it will do so in the background, in a way that will raise the cpu-load, but I don't really know how to track it. You will see the snapshot stop existing in the list, but you will not immediately see the filesystem as free. If you monitor it, and keep coming back after "a while" you will gradually see free disk increase.

aggregate snapshot usage

[root@backupberg2 ~]# zfs list -o space
NAME              AVAIL   USED  USEDSNAP  USEDDS  USEDREFRESERV  USEDCHILD
pool60             105T   181T         0   38.5K              0       181T
pool60/backups     105T   105T         0    105T              0          0
pool60/gpfs        105T  6.72T      126M   6.72T              0          0
pool60/nexsan      105T  69.7T     1.84T   67.9T              0          0
pool60/snapshots   105T  37.3K         0   37.3K              0          0

specific snapshot usage

[root@backupberg2 ~]# zfs list -t snapshot
NAME                                     USED  AVAIL  REFER  MOUNTPOINT
pool60/gpfs@20170928-1233-1506616424    10.1M      -   710M  -
pool60/gpfs@20171104-0222-1509776521    22.9M      -  6.61T  -
pool60/gpfs@20171105-0222-1509866521    24.8M      -  6.64T  -
pool60/gpfs@20171106-0222-1509952921    22.2M      -  6.66T  -
pool60/gpfs@20171107-0222-1510039321    22.7M      -  6.67T  -
pool60/gpfs@20171108-0222-1510125721    22.6M      -  6.69T  -
pool60/nexsan@20170928-1233-1506616424  1.40T      -  24.9T  -
pool60/nexsan@20171104-0222-1509776521   319G      -  64.4T  -
pool60/nexsan@20171105-0222-1509866521   472K      -  66.4T  -
pool60/nexsan@20171106-0222-1509952921      0      -  68.0T  -
pool60/nexsan@20171107-0222-1510039321      0      -  68.0T  -
pool60/nexsan@20171108-0222-1510125721      0      -  68.0T  -