nexa/docs/12-optimization-opportunities.md

# 12 — Optimization Opportunities

Observations from the running infrastructure. Each item is independent — accept, defer, or reject.

## For Nexa directly

1. **Reuse, don't redeploy.** The earlier `DEPLOYMENT.md` would have spun a second Memos / n8n / Qdrant. The current homelab already runs all three. The new [09-deployment](./09-deployment.md) treats these as pre-existing — keeps the config minimal and avoids port collisions.
2. **Use LiteLLM virtual keys per logical caller.** Today there's one SAIA key. Issuing one key per workflow (`nexa-router`, `nexa-embed`, `nexa-digest`) lets you set different per-key rate/cost limits and disable a single workflow without rotating everything.
3. **Use n8n's *credential* objects, never inline secrets.** The current workflows under `nexa-core/n8n-workflows/phase-1/*.json` should be reviewed — if any header `Authorization` is hardcoded, replace with credential references before importing.
4. **Centralise system alerts on a single ntfy topic** (`nexa.system`). Backrest, Proxmox notifications, n8n failure-webhook and the Octoprint Exited state all go to that topic; one Memos system memo aggregates them.
5. **Defer graph DB until Phase 3.4.** Qdrant alone covers ~80% of the assistant's daily value. The graph DB is justified once you actually need dependency analysis or critical-path queries.
6. **Auto-export n8n workflows.** `nexa-core/scripts/backup_workflows.sh` already exists. Schedule it inside the n8n container (cron) and let it `git commit && git push` — this is the cheapest disaster recovery.

## For the wider homelab (out of scope but worth noting)

7. **AI gateway naming.** `ai.nuclide.systems` currently proxies LobeHub (a chat UI on `:3210`), while the LiteLLM API lives on `:4000`. For Nexa, point n8n directly at LiteLLM (`http://192.168.1.40:4000` over the docker net — no public TLS hop needed) to save latency and isolate from UI restarts.
8. **MCP servers consolidation.** Dozzle shows `crawl4ai-mcp`, `markitdown-mcp`, `papersearch-mcp` running individually. They're all MCP servers — Nexa Phase-3 could pull from these via LiteLLM's MCP support to enrich the embedding pipeline (e.g. fetch + markitdown a Karakeep link before embedding).
9. **Backup the n8n SQLite file** — Backrest covers `/home/node/.n8n` if added; today the only "backup" is the workflow JSON which omits credentials and execution history.
10. **Pocket-ID SSO in front of n8n** would let you remove n8n basic-auth and unify session management across the whole stack. One-time setup, large UX win.
11. **Vaultwarden as the secret store** for Nexa secrets (`SAIA_API_KEY`, `MEMOS_API_KEY`, …) — read at bootstrap via the Bitwarden CLI from inside the docker host. Removes the need for a `.env` on disk.
12. **AdGuard as DNS-based control plane.** Since AdGuard is the resolver for the LAN, you can rewrite `*.nuclide.systems` to `192.168.1.4` (Zoraxy) internally and avoid a hairpin via the WAN — already the case if AdGuard rewrite rules are set, worth verifying.
13. **Disk usage on LXC 104** is 47.7 % (Proxmox). Monitor; n8n execution logs and Dozzle history are the usual culprits. Setting `EXECUTIONS_DATA_PRUNE=true` and `EXECUTIONS_DATA_MAX_AGE=168` (7 days) on n8n keeps it bounded.
14. **Obsidian plugin embeddings collide with Nexa's.** The vault already runs Obsidian Copilot (`.copilot`, `.copilot-index`) and Smart Connections / Smart Composer (`.smart-env`, ~13 MB). They each embed the same notes into their own vector stores — three indexes for the same content. Nexa's value is the **cross-source** index (memos + mail + obsidian + RDF graph), so it has to embed independently, but the plugins could be retired once Nexa's RAG is satisfying. Track separately, decide later.
15. **Real-time Obsidian sync via `notify_push`.** Phase 3.1 polls WebDAV every 15 min (Q4 resolution). Once that works, swap to Nextcloud's `notify_push` app for sub-second propagation. One-line workflow change in n8n.
16. **`assets/` is 186 MB of binaries** in the Obsidian vault — worth a glance to confirm it's mostly images (Phase-3.2 visual queue) rather than something that should live in Nextcloud Files proper.

## Proxmox host (NUC 14 Pro) tuning

Observed from the node summary: 22 threads, 62 GiB RAM (32 GiB used, ~24 GiB of which is ZFS ARC), 1.64 TiB disk (0.35% used), load avg <2.0, IO delay 0.04%, kernel 6.17.13-4-pve, PVE 9.1.9, EFI. Suggestions in priority order:

17. **Cap ZFS ARC.** Default is 50% of RAM (~31 GiB); current actual ~24 GiB. For a node that runs services rather than a pure storage box, capping at 8–12 GiB frees ~12–16 GiB for guests without measurable IO impact (disk is 1.64 TiB and 0.35% used — there's nothing hot to cache):
    ```
    echo 'options zfs zfs_arc_max=8589934592' > /etc/modprobe.d/zfs.conf   # 8 GiB
    update-initramfs -u
    ```
    Reboot or `echo 8589934592 > /sys/module/zfs/parameters/zfs_arc_max` to apply live.
18. **Enable KSM (Kernel Same-page Merging).** With ~40 docker containers + several LXCs, KSM typically frees 1–3 GiB by deduplicating identical memory pages. Currently `KSM sharing: 0 B` in the summary. PVE has `ksmtuned` available — `systemctl enable --now ksmtuned`.
19. **Suppress the `pve-no-subscription` repository warning** — either accept it (it's a homelab) and apply the `pve-no-subscription-warning` polyfill, or move to the enterprise repo. Pure cosmetic, but the orange banner in the UI is noise.
20. **Swap is 31 GiB on a 62 GiB box with ZFS root** — almost certainly oversized. Drop `vm.swappiness` to 10 (`sysctl -w vm.swappiness=10` + persist) so swap is only used under genuine pressure, and consider shrinking the swap volume if disk-layout permits.
21. **Verify scheduled ZFS scrub is enabled.** PVE ships `zfs-scrub-monthly@.timer` — `systemctl list-timers | grep zfs` to confirm. Cheap insurance on a 1.6 TiB pool.
22. **SMART monitoring on the NVMe.** `smartctl -a /dev/nvme0` should be regularly polled; PVE's notification target can ntfy on degradation. Combine with the existing `nexa.system` ntfy topic (optimization #4) so disk-health alerts land in the same Memos system feed as everything else.
23. **NTP source via AdGuard.** AdGuard already resolves DNS for the LAN; pointing the host's `systemd-timesyncd` at `pool.ntp.org` resolved through AdGuard avoids any external dependency for time. One-line change in `/etc/systemd/timesyncd.conf`.
24. **`fstrim.timer` enabled** for the SSD pool — verify with `systemctl status fstrim.timer`. Default-on in modern PVE, but quick to confirm.
25. **Watchdog config** is irrelevant for a single-node setup (HA is the use case), so leave the default. Mentioned only so future agents don't add it speculatively.

## Docker LXC (104) — observations & wins

Confirmed allocation: 16 CPU, 31.25 GiB RAM (7.86 GiB used / 25%), 8 GiB swap (idle), **200 GiB boot disk at 47.7% used** — disk pressure outranks RAM pressure.

26. **Fix the Intel iGPU passthrough.** The container's own notes flag the binding as "likely failing". Once `/dev/dri/{card0,renderD128}` is visible inside the LXC, both TEI and `infinity` can run embeddings on the Arc iGPU via OpenVINO / IPEX-LLM — typically **5–10× faster** than CPU. Equally, Immich's CLIP can be GPU-accelerated. The required config in `/etc/pve/lxc/104.conf`:
    ```
    lxc.cgroup2.devices.allow: c 226:0 rwm
    lxc.cgroup2.devices.allow: c 226:128 rwm
    lxc.cgroup2.devices.allow: c 29:0 rwm
    lxc.mount.entry: /dev/dri/card0       dev/dri/card0       none bind,optional,create=file
    lxc.mount.entry: /dev/dri/renderD128  dev/dri/renderD128  none bind,optional,create=file
    lxc.idmap: u 0 100000 65536
    lxc.idmap: g 0 100000 65536
    lxc.idmap: g 44 44 1            # video group on host
    lxc.idmap: g 104 104 1          # render group on host
    ```
    Then inside the container: `usermod -aG video,render <docker-user>` and run TEI with `--device cuda` replaced by the OpenVINO build (`text-embeddings-inference:cpu-1.5-openvino`). Not needed for Phase-3.1's volume but a clean upgrade path.
27. **Disk is the bottleneck, not RAM.** 95 GiB used / 200 GiB on the boot disk. Each new container Phase-3 adds (TEI image ~500 MB, infinity ~600 MB, GraphDB image + repo data ~3 GB at startup, Qdrant data growth ~50 MB per 10 k embeddings) is small in isolation but adds up. Suggestions:
    - Move **Qdrant data dir** (already inside `qdrant_scientific`) to a dedicated mountpoint on `unas` (storage pool) if it grows past ~10 GB. Until then, leave it.
    - Configure **n8n executions retention**: `EXECUTIONS_DATA_PRUNE=true`, `EXECUTIONS_DATA_MAX_AGE=168` (7 days). Already in optimization #13.
    - Schedule a **monthly `docker image prune --all --filter "until=720h"`** to recover layers from old image tags. Today's `40 containers` likely brings ≥30 dangling layers.
    - Watch **Immich**'s `upload/` and `library/` — those are the realistic 50-GB-class consumers if photo sync ramps up.
28. **The LXC has its own 8 GiB swap.** Combined with the host's 31 GiB, that's a lot of swap for guests that should never page. Drop the LXC swap allocation to 1–2 GiB (`pct set 104 -swap 2048`) — frees disk on the LVM-thin pool and forces issues to surface earlier rather than silently swap.