iscsi + restoring zfs snapshot

[Ruben]

Hi,

Still having trouble understanding this...

Any pointers?

Regards,

Ruben

On 4/12/20 11:10 AM, Ruben via freebsd-questions wrote:
> 
> Hi,
> 
> I have a couple of linux clients that mount an iscsi target provided by 
> a zfs filesystem on a FreeBSD host.
> Yesterday I messed things up and I am trying to restore a snapshot to 
> revert the changes.
> 
> I seem to be able to do so, but since the result is somewhat unexepected 
> I'm probably going the wrong way about it.  The strange thing is that 
> the snapshot restored from 2 weeks ago contains changes from last night :S
> 
> This is the FS:
> 
> zfs get all data/Docker/torrent
> NAME                 PROPERTY VALUE                  SOURCE
> data/Docker/torrent  type volume                 -
> data/Docker/torrent  creation              Sun Dec  1 21:04 2019  -
> data/Docker/torrent  used 56.8G                  -
> data/Docker/torrent  available 93.0G                  -
> data/Docker/torrent  referenced 19.7G                  -
> data/Docker/torrent  compressratio 1.00x                  -
> data/Docker/torrent  reservation none                   default
> data/Docker/torrent  volsize 30G                    local
> data/Docker/torrent  volblocksize 8K                     default
> data/Docker/torrent  checksum on                     default
> data/Docker/torrent  compression off                    default
> data/Docker/torrent  readonly off                    default
> data/Docker/torrent  createtxg 22810439               -
> data/Docker/torrent  copies 1                      default
> data/Docker/torrent  refreservation 30.9G                  local
> data/Docker/torrent  guid 15050313927458195147   -
> data/Docker/torrent  primarycache all                    default
> data/Docker/torrent  secondarycache all                    default
> data/Docker/torrent  usedbysnapshots 6.12G                  -
> data/Docker/torrent  usedbydataset 19.7G                  -
> data/Docker/torrent  usedbychildren 0                      -
> data/Docker/torrent  usedbyrefreservation 30.9G                  -
> data/Docker/torrent  logbias latency                default
> data/Docker/torrent  dedup off                    default
> data/Docker/torrent mlslabel                                     -
> data/Docker/torrent  sync standard               default
> data/Docker/torrent  refcompressratio 1.00x                  -
> data/Docker/torrent  written 17.1K                  -
> data/Docker/torrent  logicalused 12.1G                  -
> data/Docker/torrent  logicalreferenced 9.25G                  -
> data/Docker/torrent  volmode dev                    local
> data/Docker/torrent  snapshot_limit none                   default
> data/Docker/torrent  snapshot_count none                   default
> data/Docker/torrent  redundant_metadata all                    default
> 
> These are its snapshots:
> 
> zfs list -t snapshot -r data/Docker/torrent
> NAME                                           USED  AVAIL REFER  
> MOUNTPOINT
> data/Docker/torrent at 2020-02-15_09.05.00--90d   677M      - 6.30G  -
> data/Docker/torrent at 2020-02-22_09.05.00--90d   783M      - 6.57G  -
> data/Docker/torrent at 2020-02-29_09.05.00--90d   798M      - 6.65G  -
> data/Docker/torrent at 2020-03-07_09.05.00--90d   693M      - 8.71G  -
> data/Docker/torrent at 2020-03-14_09.05.00--90d   684M      - 11.2G  -
> data/Docker/torrent at 2020-03-21_09.05.00--90d   611M      - 13.9G  -
> data/Docker/torrent at 2020-03-28_09.05.00--90d   864M      - 18.1G  -
> data/Docker/torrent at 2020-04-04_09.05.00--90d  17.1K      - 19.7G  -
> [root at gneisenau:/usr/home/fux]#
> 
> This is my restore attempt:
> 
> zfs send data/Docker/torrent at 2020-03-14_09.05.00--90d | zfs receive 
> data/restoredfromsnapshot
> 
> If I unmount the FS from the client, and export this new FS instead as:
> 
>      lun 3 {
>          path /dev/zvol/data/restoredfromsnapshot
>          size 30G
>      }
> 
> , restart ctld,  mount that on the same linux client (but with the "ro" 
> option):
> 
> /dev/sdd on /mnt/restored_data type ext4 (ro,noatime,stripe=256,_netdev)
> 
> it contains :
> 
> root at torrent:/mnt/restored_data# ls -laht
> total 44K
> drwxr-xr-x  5 root root 4.0K Apr 12 10:23 ..
> drwx--x--x 14 root root 4.0K Apr 11 21:06 docker
> drwxrwxr-x  8 root root 4.0K Apr 11 20:57 .
> drwxr-xr-x  3 root root 4.0K Apr 11 20:57 deluge_config
> drwxr-xr-x  3 root root 4.0K Apr 11 20:57 docker_volumes
> drwxr-xr-x  2 root root 4.0K May 21  2019 downloads
> drwxr-xr-x  2 root root 4.0K May 21  2019 sickrage
> drwx------  2 root root  16K May 21  2019 lost+found
> root at torrent:/mnt/restored_data#
> 
> changes from way after 2020-03-14 , including those from last night .
> 
> Huh? I'm using zfSnap for creating the snapshots, like this:
> 
> /usr/local/sbin/zfSnap -s -z -a 90d -r data/Docker
> 
> My first attempt to rollback yesterday's changes involved using the 
> rollback option ( zfs rollback -r 
> data/Docker/torrent at 2020-04-04_09.05.00--90d ) but that did not work 
> either (yesterday's changes were not reverted).
> 
> Somebody got any insights as to why i'm unable to revert yesterday's 
> changes?
> 
> Any feedback appreciated!
> 
> Kind regards,
> 
> Ruben
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