> I don't know if this exists or not, but I'd like to try something like a fuse filesystem which can transparently copy a file to a fast scratch SSD when it is first accessed.
You may be interested in checking out bcache[1] or bcachefs[2].
But L2ARC only helps read speed. The idea with dm-writecache is to improve write speed.
I started thinking about this when considering using a SAN for the disks, so that write speed was limited by the 10GbE network I had. A local NVMe could then absorb write bursts, maintaining performance.
That said, it's not something I'd want to use in production that's for sure.
There was some work being done on writeback caching for ZFS[1], sadly it seems to have remained closed-source.
That's what SLOG is for if the writes are synchronous or if you have many small files/ want to optimize the metadata speed look at the metadata special device, which can also store small files of configurable size.
ZFS of course has its limits too. But in my experience I feel much more confident (re)configuring it. You can tune the real world performance well enough especially if you can utilize some of the advanced features of ZFS like snapshots/ bookmarks + zfs-send/recv for backups. Because with LVM/ XFS you can certainly hack something together which will work pretty reliably too but with ZFS it's all integrated and well tested (because it is a common use case).
As I mentioned in my other[1] post, the SLOG isn't really a write-back cache. My workloads are mostly async, so SLOG wouldn't help unless I force sync=always which isn't great either.
I love ZFS overall, it's been rock solid for me in the almost 15 years I've used it. This is just that one area where I feel could do with some improvements.
There have been and are attempts at addressing the usability gap of tech by the more tech illiterate over the years. Particularly, Linux projects such as Ordissimo[1], Eldy[2], and Endless OS[3]. I am sure there are plenty of other projects, as well (including Apple's new iPhone Assistive Access mode[4]. As sad as it may be, the market would probably be non-existent in a decade or two as newer generations enter aged care having already been somewhat familiar with computers and phone technology.
> The main problem with canaries is that it's dead easy for a government to remove them from existence, simply issue subpoenas to every website that has one.
Why can't social media platforms implement warrant canaries per user profile?
This is also a cultural thing. Compare the US to Australia for example, Australia is often remarked as very clean in comparison and the culture in Australia is to hold onto trash until it can be placed in the nearest trash bin and everything remains relatively clean in comparison (whether in urban areas or campgrounds).
Well, yes, culture is the main factor by which where you live affects cleanliness.
But the other problem in the US is that we don't have just one culture. Anyone who talks in public advocates the same pack-it-out approach to trash. That's the practice in the self-consciously outdoorsy subculture. But the people who leave trash in public campgrounds, I suspect anyway, live in an entirely different world with no realistic communication channels between them. Application to national politics is left as an exercise.
So people with disposable income leave less trash, but poor folk who go camping leave more trash behind? On the other hand you have Burningman (lots of disposable income) with at least stated goal of not leaving anything behind but drive in with gas guzzling large RVs or fly in with more gas guzzling airplanes... I don't know who is worse.
We live in a money-dependent world. We cannot go without it.