> One of the reasons why these patches are not included in the kernel is that the free space calculations do not work properly.
It seems these patches possibly fix that.
bjoli•2h ago
I wonder if I can use a smaller SSD for this and make it avoid HDD wakeups due to some process reading metadata. That alone would make me love this feature.
bionade24•1h ago
Most likely yes, but the also envisioned periodically repacking oft multiple small data extents into one big that gets written to the HDD would wake up the HDD. And if you'd make the SSD "metadata only", browser cache and logging will keep the HDD spinning.
This feature is for performance, not the case you described.
the8472•41m ago
I think you'd rather want a cache device (or some more complicated storage tiering) for that so that both metadata and frequently accessed files get moved to that dynamically based on access patterns.
Afaik btrfs doesn't support that. LVM, bcache, device mapper, bcachefs and zfs support that (though zfs would require separate caches for reading and synchronous write). And idk which of these let you control the writeback interval.
forza_user•2d ago
- https://github.com/kakra/linux/pull/36
- https://wiki.tnonline.net/w/Btrfs/Allocator_Hints
What do you think?
dontdoxxme•3h ago
It seems these patches possibly fix that.