Ship arborist corpus state to new peers and DVD-R archival via
point-in-time tar.zst packs. One artifact serves both channels —
bucket+CDN delivery and physical-media archival.
Bucket holds packs only. Pack key = hash_leaf(manifest_bytes), so same
chunk set on two writers produces the same pack_hash and upload is
idempotent. Each pack pins the corpus snapshot_root it covers in audit
+ result body — packs are delayed snapshots, not live mirrors;
falsifications between repacks produce new pack_hashes.
stream_packs runs streaming zstd over tarfile, peeking compressed-buffer
size after each chunk via FLUSH_BLOCK (preserves dictionary). Default
cap 4_400_000_000 — 4.4 GB DVD-R safe-fit, ~6.5% buffer below the
4.7 GB marketing capacity to absorb ISO9660 overhead, growisofs
lead-in/lead-out, media variance, and drive-edge refusal. Each disc
fills to ~4.4 GB recorded data, not the ~1.5 GB an uncompressed cap
produced.
One backend class (S3CompatibleBackend via boto3 + endpoint_url) covers
AWS S3, DO Spaces, R2, B2, GCS S3-interop, MinIO. Optional dep
[object-store] = boto3>=1.34; dev extras pull moto for the wire test.
Voyeur: credentials via AWS_ACCESS_KEY_ID/_SECRET_ACCESS_KEY env or
~/.aws/credentials, never printed; only endpoint URL + bucket name
surface in logs.
CLI: arborist cold {pack,unpack,stats}. Makefile: cold-pack,
cold-pack-dvd (local-dir output for growisofs), cold-unpack, cold-stats.
Sizing for current shards (14.1M chunks, ~17 GB compressed): ~4 packs
at the default cap, ~\$0.34/mo DO Spaces storage, ~\$0.0001/fresh-peer
hydrate.
Always-on raw-UTF-8 leaf store (per ticket "Hard invariants") deferred
— packs-only for now, backfill later.
2557 passed, 28 skipped, 1 xfailed.
russell@unturf.com
727cb1bd96