Trouble with snapshots . (Samba, BTRFS & Snapper)
reddit / selfhosted

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gryd3 · 2023-12-14 19:11

Not quite sure how to resolve this, but I've found myself without
access to my snapshots over the windows 'Previous Versions' dialogue.
This used to work when it was first setup a couple years ago.

For context I have :
\- An Odroid HC2 (32-bit ARM)
\- Ubuntu 20.04 (from Hardkernel) updated to 22.04
\- Samba 4.15.13-Ubuntu (with samba-vfs-modules)
\- BTRFS partition with btrfs-progs

I have also tested Samba 4.19.3 (local build) on Debian 11 (arm64) and
had the same issue.

Mount btrfs to /mnt/sda and create a subvolume at /mnt/sda/warehouse .
(mount subvol warehouse to /mnt/sda/warehouse)
Create snapper config which auto-creates a subvolume at
/mnt/sda/warehouse/.snaphots
Add user accounts to snapper config 'ALLOW\_USERS' and set 'SYNC\_ACL'
to yes.

add 'vfs objects = snapper' to smb.conf

Now I can create snapshots manually with snapper or wait for them to
auto-generate.  The snaphots appear to work properly.  I can mount the
share, and view the '.snapshots' directory and subdirectories from
within windows.. however when I check the previous versions dialogue,
it's either empty or it shows ONLY the top-most directories, but
complains they are empty when attempting to browse them.

I'm hopeful that someone know what the magic fix is for this.

Without a resolution to this, my plan is to remove snapper and use
btrbk instead so that I can use the vfs shadow\_copy2 module with a
sane snapshot naming convention of date+time instead of what's forced
within snapper.

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thekrautboy · 2023-12-14 19:12

Maybe /r/LinuxQuestions?

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gryd3 · 2023-12-14 21:03

I can give that a try if nothing shows up here. It's running on my
desk and is certainly a self-hosted item. Figured I'd give it a try
here before posting in other subs.

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thekrautboy · 2023-12-14 21:05

>  It's running on my desk and is certainly a self-hosted item

That doesnt mean that anything even remotely related to that makes
this the perfect subreddit for techsupport, right?

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gryd3 · 2023-12-14 22:26

Is it the perfect place? No, but I'm reaching out for help on a self-
hosted project for storage.  Part of the issue is that there are lots
of moving parts, so a specialized sub is likely to pass me off.
It involves Linux, Samba, BTRFS, Snapper and Windows, and the exact
location of the problem isn't well known. What would be perfect would
be finding another self-hoster that has a similar setup on a Pi or
spare PC.
I realize you don't have the answer, and that's ok. Move on to
something more productive.

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thekrautboy · 2023-12-14 22:38

Telling you a more ideal sub to get your problem solved isnt
productive?

And out of all the "moving parts" only Samba could sort ot be
considered something selfhosted.

Good luck!

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gryd3 · 2023-12-17 04:22

Switched gears:

Unable to resolve the issue with btrfs+snapper & samba+vfs\_snapper .
There's no configuration options to alter snapshot names or locations
for either the snapper application or the vf smodule.  It's supposed
to be plug+play, but just stopped working for some reason.

New solution was to deply 'btrbk' to manage snapshots and retention
policy, and use vfs\_shadowcopy2 instead.  That said: btrbk provides a
longish-format timestamp (no seconds) and the snapshots have a label
prepended to them that is specific to the subvolume you are taking a
snapshot of.  Example confguration lines to follow:

**btrbk-warehouse.conf**

    timestamp_format        long
snapshot_preserve_min   18h
snapshot_preserve       48h 7d 4w 12m 3y

volume /mnt/sda
  snapshot_dir warehouse/.snapshots
  subvolume warehouse

**smb.conf**

    [warehouse]
         vfs objects = shadow_copy2
        path = /mnt/sda/warehouse
        shadow:snapdir = .snapshots
        shadow:snapprefix = ^warehouse
        shadow:delimiter = .
        shadow:format = .%Y%m%dT%H%M
        shadow:localtime = no
        shadow:sort = desc

Snapshots are now working properly, although the setup here is a
little more involved.  Those of you using zfs instead can also use the
vfs\_shadowcopy module with sanoid instead of btrkbk. (You'll need to
adjust some of the shadow: settings. Primarily the prefix, format, and
delimiter)