I ended up with the error : There is no .ocdata âŚ
I tried different chmod and chown, starting and restarting snap nextcloud but the missing .ocdata did not disappear.
Because I was at the start there was nothing in the database yet so I sudo snap remove --purge nextcloud and deleted the data directory and the var/snap/nextcloud/ directory.
I did again sudo snap install nextcloud and followed the step one
If you just installed the snap, and havenât created an admin user yet
I think the database is now located on the harddrive but I cannot login !
The major problem is: I told my wife that we will have our own cloud to automatically save photos from the smartphone - How do I explain that I am wrong?
You need to read that wiki article again. The very first paragraph:
The partition you want to use must be mounted somewhere in /media/ or /mnt/. These are the only locations the snap can access under confinement with the removable-media plug. Connect the removable-media plug as mentioned in the README in order to grant the snap permission to access external drives.
late night:
next try and failed:
new sudo install nextcloud
changed the datadirectory to /mnt/DATA/nextcloud/data
the mount is fixed in fstab
now a new error appears:
Internal Server Error
The server encountered an internal error and was unable to complete your request.
Please contact the server administrator if this error reappears multiple times, please include the technical details below in your report.
More details can be found in the server log.
This is more than annoying !
I really cannot use nextcloud on my ssd. It is fast but too small for thousands of photos.
I like to thank you all for your patience with me.
For my excuse I like to say that I am very very new to snap and have not entered the deep sea of it yet.
I am so happy that nextcloud is running now and I do not have to find dubious excuses to tell my wife that I cannot hold up my promises.
Iâm glad youâre up and running! Please donât blame this issue on the snap or some deep sea of new tech, though. Iâve tried very hard to write decent wiki articles that answer questions like these, and you didnât even read the first paragraph where I outlined exactly what the requirements were. Please consider this a lesson for next time.
For his defence, I linked the 3rd header of the Wiki article above (though the complete page in OP), so partly my fault as well . And Iâve overseen the relevant info as well .
You did write a very decent wiki article and I am really glad you did.
But reading something and doing it is quite different. As me, I am a NEWBI to snap. I read that there has to be that removable-media connection but I had to find out how to do create it and got lost in just seeing it with snap connections âŚ
But I am still learning. I did again search and found out that I have actually create the connection with snap connect snapname:interface.
This is what I meant with the deep sea of snap - I am exploring!
Hiya, can I check and update oc_storages entry? because I am having problem and got .ocdata is missing error message.
My installation is on docker, so Iâve moved the data to another, edited config.php. I also edited data volume on my docker compose / stack to point to the new destination and still not working. So Iâm guessing itâs something to do with the db because itâs the only thing that hasnât got updated.
This is just a placeholder for where you want to store the database backup. Choose a location where the executing user has write permissions to and which you remember in case you need it at any later time. You should generally have a backup drive or location for regular Nextcloud database backup. You never know when you need it.
. And Iâve overseen the relevant info as well 
.