I am using Kubuntu 21.10, fully updated with 16GB of ram.
I have dolphin file manager set to generate thumbnails for all photos/videos. I have many stored on external encrypted drives, so I wanted to ensure that no traces are left on internal ssd like thumbnails which are usually stored in ~/.cache/thumbnails. Because this directory couldn't be changed, I found a workaround for myself by setting that directory as a 1GB ramfs so that everything in it is deleted after reboot/shutdown (w/out having to manually delete/shred the content before each shutdown, or write scripts to do this). That's always been working up to 21.10 of ubuntu, and now I am not sure.
Whenever I open a directory of photos, the thumbnails are generated quickly, even faster than on hdd or even ssd as it appears to still be done in ram. Normally though the thumbnails can be browsed in ~/.cache/thumbnails as usual, but now any thumbnails generated from files on my internal ssd are not shown in that thumbnails directory, nor is it taking up any space. I've noticed that any thumbnails generated from content on external drive's do appear as they should, and do take up space in the thumbnails directory.
Due to the low overall file size of a thumbnail, it's hard for me to determine if it's actually taking up ram on the overall system according to Ksysguard.
I have tried removing the ramfs, and letting dolphin generate the thumbnails as usual, this way they do appear in thumbnails directory, so it seems to be something connected with the ramfs but why there is an issue for thumbnails generated from internal ssd, is what I'm trying to figure out. I want to be sure these thumbnails aren't being stored somewhere else I just haven't found out yet.
Anyone know what maybe different in 21.10 that would cause this? Issue has been around since the development release of 21.10
Thank you
