Joakim Persson
947604b25d
Adds bin/mempalace-backup and docs/backup-and-recovery.md — the mechanism a palace actually needs, none of it site-specific. Why a palace cannot be backed up with cp: it is chroma.sqlite3 (authoritative), knowledge_graph.sqlite3 (usually WAL, so -wal/-shm make a plain copy a same-instant gamble), derived HNSW segment dirs, hallways.json, the embedder descriptor, and a HIDDEN .mempalace/origin.json. Both SQLite files are therefore copied through the online-backup API. Two bugs are documented because both produce a backup that looks fine: "$PALACE"/*/ silently skips the hidden dir, and per-directory rsync collides the identically named data_level0.bin in every HNSW segment. Treating the palace as one tree fixes both and makes a backup a faithful palace IMAGE, so restore is a copy rather than a procedure. Two modes: hot (default, zero downtime, ~4 s, index may lag but SQLite is authoritative and repair --mode from-sqlite rebuilds) and cold (--cold, ~5 s downtime, byte-consistent, restart trapped so a failed run still brings the server back). Verification runs on the COPY — quick_check plus row counts — and the backup is committed by mv only after it passes, with retention pruned only after a verified commit, so a broken new backup cannot delete the last good one. Documented because they are easy to get wrong: the sqlite3 CLI is often absent where the Python module is present; mempalace_embedder.json must be restored with the drawers or search silently degrades; a tested restore means running status AND search against the restored copy, since search is what actually exercises the index; mempalace-serve is a USER unit, so root systemctl reports "not found"; Persistent=true is what makes a missed window run after boot; and installing against the system Python couples the palace's availability to distribution upgrades, with the uv-managed-interpreter fix plus the two PATH traps that bite scripted upgrades. Also moves docs/synlig-primary-runbook.md out to a private fleet repository, leaving a stub that explains the split, since a host inventory is operator data for one deployment rather than part of a public toolkit. The path stays valid so existing links do not break. Remaining host references in the README, RFCs and ARCHITECTURE are left alone deliberately: they are load-bearing prose, contain no secrets, and are best generalised as they are next edited rather than in one churn-heavy pass.
20 lines
878 B
Desktop File
20 lines
878 B
Desktop File
[Unit]
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Description=MemPalace backup (hot — zero downtime, SQLite online-backup API)
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Documentation=file:%h/mempalace-toolkit/docs/backup-and-recovery.md
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# Better a skipped run than a run that creates an empty palace somewhere and
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# then dutifully backs it up.
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ConditionPathExists=%h/.mempalace/palace
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[Service]
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Type=oneshot
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# Hot mode never stops mempalace-serve. Both SQLite files are copied through the
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# online-backup API (transactionally consistent, WAL-aware); the HNSW index
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# segments are copied live and may lag a few records. That is acceptable because
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# SQLite is authoritative — see docs/backup-and-recovery.md §3.
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ExecStart=%h/.local/bin/mempalace-backup --keep 7
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# Backups are not urgent; the palace server and any running mine are. Yielding
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# CPU and I/O keeps a 4-second backup from lengthening someone's interactive
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# search.
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Nice=10
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IOSchedulingClass=idle
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