Forum Discussion

Aspirant

Nov 06, 2021

Solved

RN214 refuses to take snapshots

Hi!

After factory-resetting and reinstalling my RN214 (check out https://community.netgear.com/t5/Using-your-ReadyNAS-in-Business/Admin-page-unavailable-after-cancelled-backup-job-amp-hard/m-p/2142882/highlight/true#M193800 for details) it seems that the "smart snapshot" option is not working anymore. I don't remember doing anything differently in comparison to last time (i. e. enabling hourly smart snapshots for home folders, allowing SMB snapshot access for everyone via the directory /home/<username>/snapshot), yet the system summary shows 0 (zero) snapshots and so does the "Recover Files" dialog. Of course all directories /home/<username>/snapshot are empty.

It seems that there is no option to manually take a snapshot for home folders but thanks to BTRFS and data compression I have snapshots available for the /temp share as well and they seem to work as expected:

06 Nov 2021 10:39:39		Snapshot: Snapshot Test was successfully deleted from share or LUN Temp.
06 Nov 2021 10:39:19		Snapshot: Snapshot Test was successfully created for share or LUN Temp.
06 Nov 2021 09:44:02		System: ReadyNASOS background service started.

Firmware 6.10.5 Hotfix 1 if that matters. Is there anything I could do for further investigation? Thanks a bunch for your support!

Volker

P.S.: I have activated disk spindown after 20 minutes but allow spin up for scheduled snapshots. So that shouldn't be the problem either.

VolkerB
Nov 08, 2021
VolkerB wrote:
[...] snapshots (neither smart nor custom, no matter what schedule) did not seem to work anymore for the home shares of all users. Manual and automatic snapshots for other shares not related to individual users worked fine. There was no issue with insufficient space (no snapshot pruning taking place) [...] So I have created a new user "test" with all default settings in the "Users" group. [...] for user "test" automatic snapshots are actually taken successfully, while at the same time, no snapshots for user "volker" are stored even though he is sharing the same schedule. As it happens to be, [X] Allow snapshot access was enabled for volker and [ ] Protection was disabled, user "test" had it the other way round. [...]

Currently, I'm running a test with various combinations of (dis)allowing snapshot access and en-/disabling the protection feature, (de)activating bit rot protection and compression for the other shares to find out what exactly spoils the fun here.
The tests have completed. Conclusion:

If you don't activate the [X] Protection option in the Home Folders > Settings > Snapshot Access for all the users where snapshots should be taken, no schedule whatsoever is going to work. Everything else (Bit-rot-protection and compression for shares, snapshot access for individual users, the type of schedule and whether you want snapshots even if nothing changed) does not matter.

So if some Netgear dude is listening: Perhaps this critical relationship could at least be made more clear in the manual or probably even a warning displayed if the admin deviates from a setting that implicitely disables snapshots.

HTH & Greets,
Volker

23 Replies

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StephenB
Guru
Nov 06, 2021
I have two comments on your settings.

The "Smart" snapshots never delete the monthly snapshots. Over time, that will fill the data volume. While you can go in periodically and deleted the oldest snapshots, it is simpler to switch to "Custom", and set retention. You can also tell the system not to store snapshots if there are no changes.

Making snapshots visible in Windows has an unfortunate side effect - the snapshots are writeable, so files can be deleted by the user (or encrypted by ransomware). This is a non-started for me - so I allow Windows Previous Version, but I don't allow users to otherwise browse the snapshots.

I'm not sure what's going on in your case. But I am thinking you might try renaming or or deleting a file in one of the home folders, and see if that triggers a snapshot. FWIW, I don't use home folders myself - we don't need or want the privacy feature, and they aren't easy to restore from a backup.
- VolkerB
  Aspirant
  Nov 06, 2021
  StephenB : I think smart snapshots are quite convenient as daily snapshots are automatically promoted to weekly snapshots every Friday and become monthly snapshots at the end of every month. As only monthly snapshots are kept forever and BTFRS just stores the delta, storage issues are unlikely in low traffic situations. In contrast, the classic method just allows specifying a duration or number for snapshot retention.
  
  For snapshot access via SMB and subfolders in the user's home directory, the RN214 allows enabling "protection" (whatever that is, didn't try so far), so I figure the folder is readonly for the user in that case. I want the system to be as close to a nobrainer as possible so the option that users can browse into snapshots using the system/tools they are accommodated to and restore file versions without my help is a big plus.
  
  Using home folders at all facilitates automatic synchronization of local files quite a lot in my case (rsync, robocopy) and I don't want documents specific to the operating system or the particular user to be spread all across the public shares. The latter are for commonly used media only.
  
  Having said that: Smart snapshots in user's home folders used to work fine before (manual snapshots still do), data has been changed many times after I have done a factory reset and rebuilt the NAS. There is nothing totally obvious that I was doing differently since the first setup (with the potential exception of enabling SSH), so this is quite a mistery to me.
  
  I did compare a configuration backup before and after the factory reset (relevant differences were SSH=1 and
  TIMEMACHINE_PROTOCOL=SMB vs. TIMEMACHINE_PROTOCOL=AFP in \etc\default\services) but no changes seem causal to the issue. Of course, I can provide more detailed information if necessary, just tell me where to look.
  
  Thanks & greets,
  Volker
  - StephenB
    Guru
    Nov 06, 2021
    What firmware are you running?
    
    VolkerB wrote:
    
    I think smart snapshots are quite convenient as daily snapshots are automatically promoted to weekly snapshots every Friday and become monthly snapshots at the end of every month. As only monthly snapshots are kept forever and BTFRS just stores the delta, storage issues are unlikely in low traffic situations.
    
    Up to you of course. It was a problem for me. The "delta" over time adds up - especially in the share where I store my PC backups.
    
    "Custom" is definitely the "no brainer" config for me - it manages my overall space automatically much better. Back when I was using "smart" snapshots I had to manually delete the oldest monthly snapshots periodically.
    
    FWIW, I've never understood the benefit of the snapshot thinning. It seems to me it just risks deleting the version you want to roll back to. I much prefer the "only make snapshots with changes" setting in the custom snapshots.
StephenB
Guru
Nov 08, 2021
VolkerB wrote:

After factory-resetting and reinstalling my RN214 (check out https://community.netgear.com/t5/Using-your-ReadyNAS-in-Business/Admin-page-unavailable-after-cancelled-backup-job-amp-hard/m-p/2142882/highlight/true#M193800 for details) it seems that the "smart snapshot" option is not working anymore.

Is there anything I could do for further investigation?

I am wondering how you recreated the home folders after you did the reset. Did you restore the config files, and then just do rsync to /data/home with ssh?

Snapshot can only be made on BTRFS subvolumes, and rsync only creates ordinary folders. If you used the process above, the GUI would think the folders were btrfs subvolumes, but in fact they wouldn't be.

You could use some ssh commands to double-check (btrfs subvolume list ...) and you could also try making a snapshot from ssh (btrfs subvolume snapshot ...)
- VolkerB
  Aspirant
  Nov 08, 2021
  StephenB wrote:
  VolkerB wrote:
  After factory-resetting and reinstalling my RN214 (check out https://community.netgear.com/t5/Using-your-ReadyNAS-in-Business/Admin-page-unavailable-after-cancelled-backup-job-amp-hard/m-p/2142882/highlight/true#M193800 for details) it seems that the "smart snapshot" option is not working anymore.
  
  I am wondering how you recreated the home folders after you did the reset. Did you restore the config files, and then just do rsync to /data/home with ssh?
  No. I let the RN214 do its thing with formatting/synchronizing the RAID, then created shares for /Media, /Software, /Temp, /Backup using the management GUI and then added the users that should have access. After that, I created a "Backup job" in the management GUI to copy back data from the locally attached USB3-HDD into the relevant shares. No SSH involved.
  StephenB wrote:
  Snapshot can only be made on BTRFS subvolumes, and rsync only creates ordinary folders. If you used the process above, the GUI would think the folders were btrfs subvolumes, but in fact they wouldn't be. You could use some ssh commands to double-check (btrfs subvolume list ...) and you could also try making a snapshot from ssh (btrfs subvolume snapshot ...)
  I'm pretty convinced that the entire volume including subvolumes etc. is BTRFS since I exclusively used the RN214's GUI for that. I was just copying back naked data afterwards. Doesn't (re)activating the "[X] Protection" option to bring back snapshots for users' home directories as mentioned in my above post and the fact that snapshots always worked on shared folders of the same volume prove that everything is BTRFS?
  
  BTW, I don't remember having created subvolumes. The system is a bone stock standard setup with a couple of additional shares for data that should be accessible for all users. If there is something I could/should check via SSH to further clarify things - perhaps similar to https://www.tecmint.com/find-linux-filesystem-type/ , I'll be happy to do so.
  
  Volker
  - StephenB
    Guru
    Nov 08, 2021
    VolkerB wrote:
    BTW, I don't remember having created subvolumes.
    
    The web ui creates a subvolume automatically when you create a share. Unfortunately, home folders are treated differently. The subvolume is created the first time the user accesses the NAS using Windows - not when the user is created in the web ui (or when restoring the config files).
    
    When you restored the NAS, you needed to access the NAS from Windows using each user's credentials before you ran the backup job - and based on your description, you didn't do that. The backup job would have created ordinary subfolders in home, and not subvolumes.
    
    This would certainly explain why snapshots aren't working. You can confirm my explanation with ssh by
    
    root@NAS:~# btrfs subvol list /data | grep home
    ID 257 gen 1123683 top level 5 path home
    ID 9340 gen 1123683 top level 257 path home/admin
    
    You should see a path for each user in the output. I don't think you will.
    
    If I am correct, what you need to do to recover is
    
    rename each /home subfolder temporarily
    
    access the NAS using each user's credentials from Windows using file explorer.
    
    confirm that the subvolumes were created
    
    copy the contents of the temporary folders into the appropriate user folders
    
    delete the temporary folders.
    
    FWIW, the complexity of restoring home folders when rebuilding the NAS is one reason I've decided not to use them. I've turned off all sharing protocols in home. Creating a regular share with restricted access gives you something easier to manage - though the share isn't hidden.