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.
Thank you! I saw that there’s an official Raspberry Pi USB Dock. If I get that and another power supply, I should be in the clear, right?
One last question: How much of a problem would be an HDD instead of a SSD (Prices basically doubled since I bought the last one)? Would I just have some more initial wait times when browsing the library, but once the video is running, all work well?
Yes, if not 2x2.5" draw power from the RPi directly, it should all work fine.
Generally yes, if it needs to spin up, that might take 2-5 seconds, and you might hear the noise if the drive is in the same room. Too regular spin up/down of course also causes some mechanical wear. But I use two HDDs on my home server since around 10 years, and they still operate happily.
Due to the mechanical parts of HDDs and when powering them 24/7, I suggest to use a HDD which is made for that, a NAS drive. There are roughly 3 grades: 24/7 I/O for e.g. 24/7 camera recordings and stuff like that, 24/7 powering, when it idles in between (typical NAS use case), and everything else for end user/desktop systems which are usually not powered all the time.
This might not be representative, but my WD Red e.g. also spins up faster with less noise, and draws less power, than the (also older) WD Green that I use to store backups to. With hdparm (/etc/hdparm.conf or dietpi-drive_manager) you can then fine tune idle spindown times and in case APM level to let it spin down and maybe even power down as much as possible when not in use, but avoid too regular spin up/down on movie nights, like it should keep spinning when you are pausing for .
. 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.
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