Accidentally Lost Data via Cloud Sync - Snapshot Recovery Failed

TrueNAS General
1

Sure! Here’s a clean and detailed forum post you can use to ask for help on the TrueNAS Community Forums or Reddit (r/truenas):
Hi everyone,

I’m in a critical situation and would greatly appreciate any expert guidance.

:warning: What Happened

I have a TrueNAS SCALE setup.

My dataset is named /mnt/Data/Unica_Data and it is part of the Data pool (mirrored on 2 SSDs).

I created a Cloud Sync Task (Amazon S3) with:

Direction: PULL

Transfer Mode: SYNC

Path: /mnt/Data

Schedule: daily

Unfortunately, I made a mistake:

I misconfigured the S3 bucket (which had no files).

The sync ran with direction = PULL and sync mode, so it deleted everything in /mnt/Data to match the empty S3 bucket.

:compass: What I Tried So Far

  1. :white_check_mark: I had automatic daily snapshots (Data@auto-2025-07-15_00-00, etc.).

  2. I cloned the most recent snapshot:

zfs clone Data@auto-2025-07-15_00-00 Data/auto-2025-07-15_00-00-clone

  1. But when I checked:

ls -lah /mnt/Data/auto-2025-07-15_00-00-clone/Unica_Data

→ The directory exists but is empty.

  1. I confirmed the same across older snapshots — each one shows Unica_Data/ with no contents.

:test_tube: Additional Info

Snapshot size: ~22.8MB (Referenced)

Tried exporting the pool (zpool export Data) and re-importing readonly — no change

zfs list -t snapshot confirms consistent snapshot metadata, but no real file content is present in Unica_Data

Tried looking into zfs_recover, zfs-explorer, and zfspy, but:

Most tools are outdated or gone

Python tools fail with missing dependencies

Couldn’t find a working open-source deep ZFS recovery solution

:pray: Thank You

This is a critical production dataset, and I deeply appreciate any help or insights. If someone has been in a similar situation or knows a working ZFS recovery path, please guide me.

Thanks,
— Sohel

2

So, can you ‘cd /mnt/Data/Unica_Data/.zfs/snapshot’, can you get there? Ignore the fact you can’t see .zfs if you do a ls command.

I don’t know if the pull can mess with that or not. And presuming you did recursive snapshots. Not sure I follow all you wrote, just a quick response before I have to go.

3

Can you please connect on remote to see everything :pray:

4

How would I do that?

5

I will you give you anydesk to se this

6

You would have to send me a private message of course.

1 Like
7

Where I send message?

I can’t show here.

8

I sent you a message with my email address, use it. Not sure where they (dms) show up, I suppose notifications and bottom left of the forums screen.

I’m not sure I’d recommend having random people on the internet try and help by logging into your system, but that is up to you. I’ve been here a long time so maybe that counts for something.