Dolphin is not caching the previews of files on LUKS encrypted volumes. This means they are regenerated upon every navigation which is incredibly slow.
From what I gather this is to stop “leakage” onto an unencrypted volume (/~/.cache/.thumbnails)
However, I would like these thumbnails cached. Is there a way to achieve this?
KDE Plasma 5.27.11
KDE Frameworks 5.115.0
Qt 5.15.12
An unpleasant and needlessly aggressive reply 
Surely it would be nice to have the option? Or the cache could be relocated on to the encrypted volume?
I would much appreciate any helpful advice.
Hi - not sure myself how to approach the issue, but just for reference in the discussion - there are two previous and one current KDE Bugtracking System reports that stick out as having potentially relevant context here about when thumbnailing is allowed and where it should be performed:
Hi Johnandmegh
Thanks for those links. The solution seems to be that if your /home is encrypted then what I proposed is quite feasible. In this case I moved my /home to a partition encrypted with LUKS2 and bingo the thumbnails are cached from other encrypted volumes. Much appreciate your helpful input.
JohnBrown - put that in your pipe and smoke it.
On my system, I have an SSD using LVM on LUKS with root and home partitions. Media on those partitions does cache thumbnails.
I then have two HDDs with a regular LUKS volume each mounted with crypttab+fstab to /mnt. But thumbnails of media on those drives will not cache.
I did find that linking the mount points of those two drives to home and browsing them though those will then cache thumbnails, but that seems like a hacky workaround?
Is there a setting I’m overlooking, am I mounting those drives wrong, or is that just still how it is? I don’t quite get the meaning of some of the responses in those issues.