Enabling and disabling "Allow Snapshot Access" deleted snapshots but not "snapshot" folder
Running OS 6.9.5, I wanted to recover a file that I thought might still be available in a snapshot. So, I checked "Enable snapshot access" for the share and took a look. No liuck finding the file, so I went back and unchecked the box. But, the "snapshot" folder is still there (both in the GUI and via SMB) and it is now empty. It's bad enough that i lost my snapshots, but did the system really revert back to not showing snapshots since the folder is still visible? Can I safely delete the "snapshots" folder? Based on the fact that the "recover" option is greyed out and the indicator for space used by snapshots has decreased, I believe the snapshots really are gone. But is there some place I should look and see if they are "hiding"?
I know I have enabled and then disabled snapshot access before with no problems, so this is clearly a bug that has gotten into the OS at some point since I last did it.
Can you check from SSH if the snapshots are there.
btrfs subv list -s /data/
Do you see any entries here for your share? Turning off snapshot access should make the "snapshot" folder inaccessible via SMB/NFS but not delete your snapshots! Can you try and reboot NAS after turning off snapshot access?
A little testing here. I made a test share on my NAS: "Test". I enable snapshot access on this folder and I can see the snapshots folder being visible inside, as expected.
root@Datastore:~# ls -l /data/Test/
total 0
drwxr-xr-x 2 root root 40 Mar 30 17:49 snapshot
The snapshots folder is actually mounted when you enable snapshot access. The snapshots folder is a subvolume in itself.
root@Datastore:~# mount | grep Test
tmpfs on /data/Test/snapshot type tmpfs (rw,noatime,nodiratime,size=4k)
So anyway, I start taking snapshots (from the GUI) and they are visible inside the snapshots folder, as expected. I can also access this over SMB/NFS.
root@Datastore:~# ls -l /data/Test/snapshot/
total 0
drwxrwxrwx+ 1 guest guest 126 Mar 30 17:51 m_snap1
I confirm the snapshot is indeed there, just for clarity.
root@Datastore:~# btrfs subv list -s /data/ | grep Test
ID 1007 gen 908 cgen 908 top level 1006 otime 2019-03-30 17:54:26 path Test/.snapshots/1/snapshot
I turn off snapshot access on my share. My snapshots folder is gone from the share and I can no longer see if over SMB/NFS.
root@Datastore:~# ls -l /data/Test/
total 0
The snapshots folder is not longer mounted either.
root@Datastore:~# mount | grep Test
root@Datastore:~#
The snapshot still exists though.
root@Datastore:~# btrfs subv list -s /data/ | grep Test
ID 1007 gen 908 cgen 908 top level 1006 otime 2019-03-30 17:54:26 path Test/.snapshots/1/snapshot
So, it is not a bug in the firmware itself I would say as I run 6.9.5 too. More likely is that something in your config got skewed somehow. Start by checking if the snapshots are actually there, from the CLI. Also, check if that snapshots folder still mounted? If it is, you can probably just un-mount the snapshots folder (or try to reboot NAS).
Re: Enabling and disabling "Allow Snapshot Access" deleted snapshots but not "snapsh
The snapshots were really gone. After disabling snapshot access, I was able to create new snapshots, and they were not visible in the folder but did show up as snapshots in the GUI. I then deleted the still-persistent "snapshot" folder, and all seems well.
The volume is on an EDA500-like eSATA chassis, and I've found other oddities happening there. So maybe that was a factor.
I just got things "settled down" following a failure of the volume on my real EDA500. Maybe I'll try some experiments later in the week and see if it was just a fluke. Fortunately, it's old archival data and not often changed (like, not in the last year), so the snapshots weren't important. Apparently, the file I was looking for was never archived.
