1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
|
I love [NextCloud](https://nextcloud.com). Nextcloud allows me to have all the convenience of Dropbox, but hosted by me, controlled by me, and customized to suit my needs. I mainly use the file syncing, calendar, and contacts features, but Nextcloud can do a crazy amount of things.
The problem with NextCloud, and maybe you could argue that this is the price you pay for the freedom and control, is that I find it requires a bit of maintenance to keep it running smoothly. Nextcloud does some decidedly odd things from time to time, and knowing how to deal with them can save you some disk space and maybe avoid syncing headaches.
I should note, that while I call these problems, I **have never lost data** using Nextcloud. These are really more annoyances and some ways to prevent them than *problems*.
### How to Get Rid of Huge Thumbnails in Nextcloud
If Nextcloud is taking up more disk space than you think it should, or your Nextcloud storage space is just running low, the first thing to check is the image thumbnails directory.
At one point I poked around in the Nextcloud `data` directory and found 11-gigabytes worth of image previews for only 6-gigabytes worth of actual images stored. That is crazy. That should never happen.
Nextcloud's image thumbnail defaults err on the side of "make it look good in the browser" where as I prefer to err on the side of keep it really small.
I did some research and came up with a few solutions. First, it looks like my runaway 11-gigabyte problem might have been due to a bug in older versions of Nextcloud. Ideally I will not hit that issue again. But, I don't admin servers with hope and optimism, so I figured out how to tell Nextcloud to generate smaller image previews. I almost never look at the images within the web UI, so I really don't care about the previews at all. I made them much, much smaller than the defaults. Here's the values I use:
~~~bash
occ config:app:set previewgenerator squareSizes --value="32 256"
occ config:app:set previewgenerator widthSizes --value="256 384"
occ config:app:set previewgenerator heightSizes --value="256"
occ config:system:set preview_max_x --value 500
occ config:system:set preview_max_y --value 500
occ config:system:set jpeg_quality --value 60
occ config:app:set preview jpeg_quality --value="60"
~~~
Just ssh into your Nextcloud server and run all these commands. If you followed the basic Nextcloud install instructions you'll want to run these as your web server user. For me, with NextCloud running on Debian 10, the full command looks like this:
~~~bash
sudo -u www-data php /var/www/nextcloud/occ config:app:set previewgenerator squareSizes --value="32 256"
sudo -u www-data php /var/www/nextcloud/occ config:app:set previewgenerator widthSizes --value="256 384"
# and so on, running all the commands listed above
~~~
This assumes you installed Nextcloud into the directory `/var/www/nextcloud`, if you installed it somewhere else, adjust the path to the Nextcloud command line tool `occ`.
That will stop Nextcloud from generating huge preview files. So far so good. I deleted the existing previews and reclaimed 11-gigabytes. Sweet. You can pre-generate previews, which will make the web UI faster if you browse images in it. I do not, so I didn't generate any previews ahead of time.
### How to Solve `File is Locked` Issues in Nextcloud
No matter what I do, I always end up with locked file syncing issues. Researching this led me to try using Redis to cache things, but that didn't help. I don't know why this happens. I blame PHP. When in doubt, blame PHP.
Thankfully it doesn't happen very often, but every six months or so I'll see an error, then two, then they start piling up. Here's how to fix it.
First, put Nextcloud in maintenance mode (again, assuming Debian 10, with Nextcloud in the `/var/www/nextcloud` directory):
~~~bash
sudo -u www-data php /var/www/nextcloud/occ maintenance:mode --on
~~~
Now we're going directly into the database. For me that's Postgresql. If you use Mysql or Mariadb, you may need to adjust the syntax a little.
~~~bash
psql -U yournextclouddbuser -hlocalhost -d yournextclouddbname
password:
nextclouddbname=> DELETE FROM oc_file_locks WHERE True;
~~~
That should get rid of all the locked file problems. For a while anyway.
Don't forget to turn maintenance mode off:
~~~bash
sudo -u www-data php /var/www/nextcloud/occ maintenance:mode --off
~~~
### Force a File Re-Scan
If you frequently add and remove folders from Nextcloud, you may sometimes run into issues. I usually add a folder at the start of a new project, and then delete it when the project is finished. Mostly this just works, even with shared folders, on the rare occasion that I used them, but sometimes Nextcloud won't delete a folder. I have no idea why. It just throws an unhelpful error in the web admin and refuses to delete the folder from the server.
I end up manually deleting it on the server using: `rm -rf path/to/storage/folder`. Nextcloud however, doesn't always seem to notice that the folder is gone, and still shows it in the web and sync client interfaces. The solution is to force Nextcloud to rescan all its files with this command:
~~~bash
sudo -u www-data php /var/www/nextcloud/occ maintenance:mode --on
sudo -u www-data php /var/www/nextcloud/occ files:scan --path="yournextcloudusername/files/NameOfYourExternalStorage"
sudo -u www-data php /var/www/nextcloud/occ maintenance:mode --off
~~~
Beware that on large data directories this can take some time. It takes about 30 seconds to scan my roughly 30GB of files.
### Mostly Though, Nextcloud is Awesome
Those are three annoyances I've hit with Nextcloud over the years and the little tricks I've used to solve them. Lest anyone think I am complaining, I am not. Not really anyway. The image thumbnail thing is pretty egregious for a piece of software that aims to be enterprise grade, but mostly Nextcloud is pretty awesome.
I rely on Nextcloud for files syncing, Calendar and Contact hosting, and keeping my notes synced across devices. Aside from these three things, I have never had a problem.
####Shoulder's Stood Upon
* [Nextcloud's documentation](https://docs.nextcloud.com) isn't the best, but can help get you pointed in the right direction.
* I tried a few different solutions to the thumbnail problem, especially helpful was this post on [Understanding and Improving Nextcloud Previews](https://ownyourbits.com/2019/06/29/understanding-and-improving-nextcloud-previews/), but nachoparker.
* The [file lock solution](https://help.nextcloud.com/t/file-is-locked-how-to-unlock/1883) comes from the Nextcloud forums.
* The solution to scanning external storages comes from the [Nextcloud forums](https://help.nextcloud.com/t/automate-occ-filescan/35282/4).
|
