[zfs-discuss] Debian: snapshots not mounted in .zfs/snapshots

[Mickaël Raybaud-Roig]

Hello,

We are using ZFS on a Debian server running LXC containers.
This server has a ZFS filesystem called 'pool1/backups/vm/155' wich
contains several snapshots :

    # zfs list -r -t snapshot pool1/backups/vm/155
    NAME                             USED  AVAIL  REFER  MOUNTPOINT
    pool1/backups/vm/155 at day-5       143M      -  23,5G  -
    pool1/backups/vm/155 at day-6       106M      -  23,5G  -
    pool1/backups/vm/155 at day-7          0      -  23,5G  -
    pool1/backups/vm/155 at week-4         0      -  23,5G  -
    pool1/backups/vm/155 at day-1       107M      -  23,5G  -
    pool1/backups/vm/155 at day-2       107M      -  23,6G  -
    pool1/backups/vm/155 at day-3        88K      -  23,6G  -

When I try to access a snapshot using the directory '.zfs/snapshots',
I get the following error :

    # LC_ALL=C ls /storage/pool1/backups/vm/155/.zfs/snapshot/day-1
    ls: cannot open directory
/storage/pool1/backups/vm/155/.zfs/snapshot/day-1: Too many levels of
symbolic links

    # LC_ALL=C cd /storage/pool1/backups/vm/155/.zfs/snapshot/day-1
    -bash: cd: /storage/hd/backup/latest/1055/.zfs/snapshot/daily-1:
Too many levels of symbolic links

I am able list the content of the dicectiory
'/storage/pool1/backups/vm/155/.zfs/snapshot/day-1', but I can't
access the snapshots :

    # LC_ALL=C ls -l -a  /storage/pool1/backups/vm/155/.zfs
    total 1
    dr-xr-xr-x 1 root      root      0 Apr 28 11:21 .
    drwxr-x--- 5 user1     user1     5 Apr 28 10:25 ..
    dr-xr-xr-x 2 root      root      2 Apr 28 11:21 shares
    dr-xr-xr-x 2 root      root      2 Apr 27 23:03 snapshot

    # LC_ALL=C ls -l -a  /storage/pool1/backups/vm/155/.zfs/snapshot
    total 0
    dr-xr-xr-x 2 root root 2 Apr 27 23:03 .
    dr-xr-xr-x 1 root root 0 Apr 28 11:21 ..
    dr-xr-xr-x 1 root root 0 Apr 28 11:21 day-1
    dr-xr-xr-x 1 root root 0 Apr 28 11:21 day-2
    dr-xr-xr-x 1 root root 0 Apr 28 11:21 day-3
    dr-xr-xr-x 1 root root 0 Apr 28 11:21 day-5
    dr-xr-xr-x 1 root root 0 Apr 28 11:21 day-6
    dr-xr-xr-x 1 root root 0 Apr 28 11:21 day-7
    dr-xr-xr-x 1 root root 0 Apr 28 11:21 week-4

    # LC_ALL=C cd /storage/pool1/backups/vm/155/.zfs/snapshot/week-4
    -bash: cd: /storage/hd/backup/latest/1055/.zfs/snapshot/week-4:
Too many levels of symbolic links

The snapshots where created recursively with the following command :

    zfs snapshot -R pool1/backups/vm at name

The directory /storage/pool1/backups/vm/155 is also bind-mounted in a
LXC container running in the server.
I have the same error if I try to access the snapshot (using
".zfs/snapshot/<snapshit name>") from inside the container.

How can I access the snapshots without having to mount them manually ?



Here is our configuration of ZFS :

    # zfs list -r pool1
    NAME                              USED  AVAIL  REFER  MOUNTPOINT
    pool1                            1,21T  2,30T    96K  /storage/pool1
    pool1/backups                    1,05T  1,39T   232K  /storage/pool1/backups
    pool1/backups/vm                 49,2G  1,39T   104K
/storage/pool1/backups/vm
    pool1/backups/vm/155             24,1G  1,39T  23,6G
/storage/pool1/backups/vm/155

    # zfs get all pool1/backups/vm/155 | grep snap
    pool1/backups/vm/155  snapdir               hidden
         default
    pool1/backups/vm/155  usedbysnapshots       573M
         -
    pool1/backups/vm/155  snapshot_limit        none
         default
    pool1/backups/vm/155  snapshot_count        none
         default
    pool1/backups/vm/155  snapdev               hidden
         default

We are using ZoL 0.6.5 on Debian 8.4 :

    # cat /etc/debian_version
    8.4

    # uname -a
    Linux hostname 4.2.8-1-pve #1 SMP Sat Mar 19 10:44:29 CET 2016
x86_64 GNU/Linux

    # dpkg --list | grep zfs
    ii  libzfs2                        0.6.5-pve7~jessie
amd64        Native ZFS filesystem library for Linux
    ii  zfs-initramfs                  0.6.5-pve7~jessie
amd64        Native ZFS root filesystem capabilities for Linux
    ii  zfsutils                       0.6.5-pve7~jessie
amd64        command-line tools to manage ZFS filesystems


Best regards,

---
Mickaël