The claim that hydration-as-a-borrow makes peak disk the working set
rather than the library was so far an argument. `--example vfs_cycle`
runs it: 100 photographs of 25 MB, 90 dehydrated, a pass over all of
them through the real engine.
Peak 275 MB — the resting set plus one photograph — against 2,500 MB
had the pass simply fetched everything. Back to 250 MB afterwards, and
all ten files the user already kept still there, which is the half of
the contract that matters more.
Recorded in docs/storage.md §6.3 and ARCH §9.0a, because a bound argued
from a number nobody measured is one that gets quietly lost.
The folder connector declares `LocalEtags`, which means the engine walks
the whole library on every scan with no pruning. That is the honest
capability, and the argument for it being affordable was so far an
assertion about `stat` versus `PROPFIND`.
`--example scan` runs the real path — `dr_sync::scan` over the connector,
then a ranged read of the kind the thumbnail worker makes. Read-only; it
never writes into the folder it is pointed at.
2,299 images across 233 directories in 137 ms, and 380 across 13 in
29 ms. Against 34.1 s for 17,185 RAWs over WebDAV *with* pruning
available. Recorded in docs/storage.md §5.2 and ARCH §8.4a, because a
capability trade-off argued from a number nobody measured is the kind
that gets quietly reversed later.
dtourolle