When I do OS updates (Fedora, so that's dnf and rpm) with a system on USB flash or SD Card flash, the write are abysmal. Like, 3-4MB/s, using `iotop -d3 -o`. Th

When I do OS updates (Fedora, so that's dnf and rpm) with a system on USB flash or SD Card flash, the write are abysmal. Like, 3-4MB/s, using `iotop -d3 -o`. There's almost no reads suggesting the RPMs that have been downloaded are cached. I experience this with ext4, btrfs, and f2fs. Using strace on both dnf and rpm, there's no appreciable amount of sync(), fsync(), or fdatasync() - so I'm not really sure why there was this persistent ~4MB/s trickle to the card rather than large "state" updates, in particular for f2fs and Btrfs. All three make heavy use of delayed allocation, but in particular f2fs and Btrfs have no specifically designated locations for write, or overwrites. So I'd expect that most update OS type writes should/could be much faster. A sequential write is ~20MB/s on both of these media, and sequential reads are ~150MB/s. I wasn't ever able to profile it well enough to understand why it's so dog slow.