[wtallis]

I didn't mean to be incendiary, just to point out that different experiences could be leading people to make inaccurate assumptions.

And I'm a bit confused by what you mean when you say "caching filesystem", since you seem to be using that term to talk about something that isn't a filesystem at all, rather than a filesystem that has advanced caching capabilities on its feature list. (cf. terms like "checksumming filesystem", "copy on write filesystem", "journalling filesystem") I was careful to refer to the original bcache and similar tools as "caching layers" rather than mislabel them as filesystems, but bcachefs is a proper filesystem.

[dijit]

A caching filesystem (as opposed to a standard block storage filesystem) would be one used for cached data specifically. ZFS has cache drives but the actual on disk layout does not resemble ZFS as we know it. That’s what I’m eluding to;

ZFS in this case is an all-in-one solution so it’s perfectly fine to refer to it as a feature of the filesystem, but externalising that to a separate agnostic product would result in this being exposed.

In fact CacheFS was designed exactly like this, and as you can see includes both “cache” and “FS” in the name.

https://lwn.net/Articles/100330/