Okay, I found the documentation: Internal implementation of Pools, Shares, Snapshots and Clones
Snapshot is a BTRFS snapshot of a Subvolume(aka Share). Snapshots of a Share are placed in /mnt2/<pool name>/.snapshots/<share name>/<snapshot name>.
So here’s what’s in /mnt2/rockons/.snapshots/mariadb-data:
drwxr-xr-x 1 mariadb mariadb 228 Nov 29 03:42 mariadata_201611290342
drwxr-xr-x 1 mariadb mariadb 228 Nov 29 03:42 mariadata_201612040300
drwxr-xr-x 1 mariadb mariadb 228 Dec 6 03:42 mariadata_201612060342
drwxr-xr-x 1 mariadb mariadb 550 Feb 18 01:30 mariadata_201702180150
drwxr-xr-x 1 mariadb mariadb 596 Feb 18 01:50 mariadata_201702180250
drwxr-xr-x 1 mariadb mariadb 642 Feb 18 02:50 mariadata_201702180350
drwxr-xr-x 1 mariadb mariadb 688 Feb 18 03:50 mariadata_201702180450
drwxr-xr-x 1 mariadb mariadb 734 Feb 18 04:50 mariadata_201702180550
drwxr-xr-x 1 mariadb mariadb 780 Feb 18 05:50 mariadata_201702180650
drwxr-xr-x 1 mariadb mariadb 780 Feb 18 06:50 mariadata_201702180750
drwxr-xr-x 1 mariadb mariadb 780 Feb 18 07:50 mariadata_201702180850
drwxr-xr-x 1 mariadb mariadb 780 Feb 18 08:50 mariadata_201702180950
drwxr-xr-x 1 mariadb mariadb 780 Feb 18 09:50 mariadata_201702181050
drwxr-xr-x 1 mariadb mariadb 780 Feb 18 10:50 mariadata_201702181150
drwxr-xr-x 1 mariadb mariadb 780 Feb 18 11:50 mariadata_201702181250
drwxr-xr-x 1 mariadb mariadb 228 Oct 25 03:42 reverted-working-againSo it sure looks like none of my daily, weekly, or monthly snapshots are being taken. Which is pretty alarming.
(EDIT: Almost none. On a second look, the 1:30 AM snapshot is a daily snapshot. However, as of the following morning, it’s gone. There’s a new daily snapshot for Feb 19, but the Feb 18 one isn’t there anymore. So it appears that daily snapshots are being taken, but that they’re being treated as if the “Maximum Count” setting were 1 instead of 7.)
For an example of how I’m doing it, here’s how the Daily snapshot is set up:
Task name: snapshot-mariadata-daily
Task type: snapshot
Share: mariadb-data
Snapshot prefix: mariadata
Maximum count: 7
Make snapshots writable? Yes (was previously no; have changed to Yes at @Flyer’s suggestion)
Make snapshots visible? Yes
Enable task? Yes
Task frequency: Every day at 01:30
The Daily snapshot says that it finished, every day for the past 15 days.
The Weekly snapshot says that it finished on February 14th and 7th, errored on January 31st, 24th, 7th, and 10th, and finished on January 3rd and December 27th, 20th, and 13th.
The Monthly snapshot says that it had en error on February 4, but that it finished on January 4.
First of all, can anyone figure out what’s happening? If the daily, weekly, and monthly snapshots are finishing, why aren’t they showing up in /mnt2/rockons/.snapshots/mariadb-data? Is there anywhere else they could possibly be? (I notice that /mnt2/rockons/.snapshots/owncloud-data doesn’t even exist, and yet I can see OC snapshots in the Web interface. They must be somewhere. EDIT: I remembered owncloud-data is on a different pool.)
And second, what are my options at this point? Is there anything I can do besides wiping out my database and starting over from the beginning? Is there a way I can get Owncloud to attempt to repair the DB without having access to its web GUI?