This setup works flawlessly (after tinkering with the permissions a bit). It works a bit too well, actually - my SSD is nearing its storage limit . Currently, I’m running dietpi-backup to backup all files except the Videos folder to the HDD. I’d like to keep it that way.
My problem:
I want to get more space - another SSD just for videos.
My plan:
Mount new SSD on /mnt/videossd/
Move /mnt/dietpi_userdata/nextcloud_data/my_user/files/Videos to /mnt/videossd/Videos
Could this work? Can I do this somehow without step 2 (I assume it would take a long time, and I am impatient )? Could I get problems with the power if both SSDs are only powered via USB?
Generally this can work well, also permissions are kept if you mv or cp -a the directory. The USB power concern however is valid: On earlier RPi models this would definitely not work, even with a single 2.5" HDD/SSD powered via USB on an RPi 4 is a common reason for issues. However, with the RPi 5, things have changed a bit, let’s see: https://www.raspberrypi.com/documentation/computers/raspberry-pi.html#maximum-power-output
Hmm, in the table, it does not explicitly say that the 600/1600 mA are shared between all USB ports, but I remember this was not the case anymore on the RPi 5, only on the earlier models (as the table says). However, the red box below the RPi 5 heading again says:
The power budget is shared between the USB ports and the fan header.
So with a 5A PSU, 1600 mA * 5V = 8W. This should be solid for any 2.5" drive, but not if shared between two of them. I mean a 5A PSU cannot power 4*1.6A + the RPi 5 of course, so it probably makes sense that the 1.6A are still shared, which means two 2.5" drives will likely run into issues, especially when both do I/O concurrently, copying things from one to the other or so => better have a dedicated PSU/docking station or so. Else, if you want to test it, create some test data and copy them back and forth to create some concurrent load as stress test or so.
. Currently, I’m running dietpi-backup to backup all files except the Videos folder to the HDD. I’d like to keep it that way.