P: Allow configuration of location and max size of preview and smart preview cache

[Mark_Woon]

I would really like to see a way to configure the location and max sizes of the preview and smart preview cache.If I could move the preview/smart preview cache away from the Lightroom catalog, this would allow me to easily sync the catalog via Dropbox/OneDrive/etc.I'd also like to set a max size for the preview and smart preview cache (so I don't run into space issues on smaller SSD drives). Once max size is hit, it can cull old/unused cache entries.

[DonkeyPhotez]

I definitely back Your two ideas because they (also) imply for the user to become (more) conscious of the whereabouts of theses folders/cache.
(Idea : In preferences; such as with existing link "show catalogue in explorer").
Helpful to understand backup strategies (of our own).
( Also add "show me my presets location", etc.,.)
( Your idea to me is not only practical but to become conscious about the weight of such each folder, is good, in addition excellent the proposed option for rules to overwrite if desired.) 

[FeedbackCommunityMember]

I'd just like to add to this. It's a major issue. I want previews to live on my SSD in my laptop, but they grow faster than I can add disk space.

[keg415]

Allow the location of the previews cache to be changed so that it can be stored separately from the catalog.  This would allow the previews to be stored on an SSD to improve performance when the catalog is stored on a slower devce, e.g. a network drive.

[Ian Lyons]

The catlog cannot be stored on a network drive or NAS. If you try it, you'll get an error message or worse!

Ideally, the catalog should be stored on your fastest drive.

[keg415]

Yes, a catalog can be stored reliably on a network drive by using a workaround to avoid the error message that normally prevents this.  I've used catalogs on a NAS for over a decade without experiencing corruption and I've researched why this is technically sound.  See details and references at https://github.com/kgorlen/lightroom.

It's also currently possible to have the preview cache on a local SSD with the catalog on a network drive.  But it's bad practice because the workaround to enable this causes the .lrcat.lock, .lrcat-shm, and .lrcat-wal files to reside on a different storage device than the catalog.