Frank
55f87fcdce
The 2026-10-09 wire aliases become the service names everywhere: systemd units, serve scripts, env files and FRANK_* variables, deploy-plan/deploy-remote service keys, container names, Prometheus job names + alert rules, Grafana dashboard queries, bats seams, runbook filenames, homepage/AGENTS lore, and historical prose. Rollback tags renamed in lockstep. Residue in the tree: zero. Retired frank-medium/small/npu names are history and stay. Known casualty: scripts/patches/*.patch context lines were rewritten; those retired-era vLLM-fork patches no longer apply byte-exact.
143 lines
6.2 KiB
Markdown
143 lines
6.2 KiB
Markdown
---
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type: configuration
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title: Dankclaw Swap Configuration
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description: The host swapfile on Dankclaw — 64 GiB at /swap.img on ext4, fstab-driven via the generated swap.img.swap unit. Covers why it was raised from 8 GiB, the safe resize ordering that avoids an OOM on a host whose MemAvailable is inflated by pinned model weights, and the swappiness caveat.
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tags:
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- dankclaw
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- host
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- memory
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- swap
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timestamp: 2026-09-12
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---
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# Dankclaw Swap Configuration
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**Host:** Dankclaw (192.168.0.143) — **Filesystem:** ext4 on `/dev/nvme0n1p2`
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| Item | Value |
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| --- | --- |
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| Swapfile | `/swap.img` |
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| Size | **64 GiB** (raised from 8 GiB on 2026-09-12) |
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| Filesystem | ext4 — swapfiles fully supported, no btrfs `nocow` handling needed |
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| Allocation | `fallocate` (preallocated, hole-free; 530 extents) |
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| Persistence | `/etc/fstab` line 12: `/swap.img none swap sw 0 0` |
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| systemd unit | `swap.img.swap` — `loaded (/etc/fstab; generated)`, `active` |
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| `vm.swappiness` | `60` (distro default, unchanged) |
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| zswap | disabled (`/sys/module/zswap/parameters/enabled` = `N`) |
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| Free on `/` after | 748 GiB of 1.9 TiB |
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The unit is **generated from fstab**, not a hand-written unit file. fstab is the
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only control point; `systemctl daemon-reload` re-reads it. Nothing in this
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repository references the swapfile — it is host-level state, documented here so
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it is not invisible.
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## Why 64 GiB
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Dankclaw is shared. `frank-dragoon` alone holds **103.5 GiB of the 121.2 GiB**
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host (`68.0 weights + 14.4 KV pool + 21.1 working`), leaving roughly
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**7.1 GiB** for 28 co-tenant containers whose working set is ~4.3 GiB. The
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engine itself warns that when that runs out, frank-dragoon and its neighbours
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"can stall for minutes at a time at full CPU with no disk activity and no
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output". Swap is the valve that turns an OOM kill into slow paging.
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Swap does **not** relieve the pinned-weights problem — see the caveat below.
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It protects the *co-tenants* and buys headroom for burst allocation.
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## The safe resize ordering
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You cannot grow an active swapfile; it must be swapped off first. On a host
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like this, **never `swapoff` before the replacement is online.** The old 8 GiB
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held 4 GiB of live pages, and `MemAvailable` read 73 GiB while only ~5 GiB was
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genuinely free — the pinned model weights are counted as reclaimable page
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cache, so the headline number is a lie by roughly the size of the model
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(see [[halogen-flash-server]]). Swapping off into that apparent space, with
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nothing else to receive the pages, is how you invite the OOM killer.
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The ordering that avoids it — create and enable the new swap **first**, so the
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pages have somewhere to go:
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```bash
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# 1. Preallocate + format + enable the replacement, old swap still live
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sudo fallocate -l 64G /swap2.img
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sudo chmod 600 /swap2.img
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sudo mkswap /swap2.img # also rejects files with holes
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sudo swapon /swap2.img # total swap now 72 GiB
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# 2. Only now drain the old one — pages migrate into /swap2.img, not into RAM
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sudo swapoff /swap.img # took 65 s for 4 GiB
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# 3. Consolidate onto the conventional path so fstab needs no edit
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sudo swapoff /swap2.img # 725 MiB left, trivial
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sudo mkdir -p ~/.AGENTTRASH/20260912-swapfile-8g
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sudo mv /swap.img ~/.AGENTTRASH/20260912-swapfile-8g/swap.img
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sudo mv /swap2.img /swap.img
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sudo swapon /swap.img
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```
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Step 3 is chained tightly because it leaves the host with **zero swap** for a
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few seconds. Do not leave that window open.
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`mkswap` succeeding is itself a check: it refuses swapfiles containing holes,
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so a `fallocate` that produced a sparse file fails here rather than at 3 a.m.
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under memory pressure.
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## Verification
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```bash
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swapon --show=NAME,TYPE,SIZE,USED,PRIO # /swap.img file 64G
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systemctl is-active swap.img.swap # active
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grep swap /etc/fstab # line 12 intact -> boot persistence
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free -h | tail -2 # Swap: 63Gi total
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```
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Then confirm the inference service is unaffected — a completion, not just
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`/health`:
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```bash
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curl -s http://127.0.0.1:7770/v1/chat/completions \
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-H 'Content-Type: application/json' \
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-d '{"model":"frank-dragoon","messages":[{"role":"user","content":"Reply with exactly: SWAP64-OK"}],"max_tokens":48,"reasoning_effort":"low"}'
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```
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As run 2026-09-12: `finish_reason: stop`, `SWAP64-OK`, 28 containers up,
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frank-dragoon `health=200` throughout.
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## Caveats
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- **Swap cannot help the pinned weights.** frank-dragoon's ~68 GiB of weights are
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held deliberately; paging them is a stall, not a relief. More swap does not
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make the doubled KV pool affordable — see the reserve/pool ceiling in
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[[halogen-flash-server]].
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- **`vm.swappiness=60` is untested against this workload.** Under real
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pressure the kernel will happily page anonymous memory, and frank-dragoon's KV
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pool and working set *are* anonymous. Swapping the KV pool would be far worse
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than the OOM kill it prevents. If the box ever starts thrashing, lowering
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swappiness (or capping the engine's cgroup) is the knob, not more swap.
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- **`free` still lies after the change.** `MemAvailable` reads ~70 GiB while
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the model is loaded. Trust the engine's `host memory left for everything
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else` line, not `free`.
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- **Filesystem prerequisite (other hosts).** ext4 and xfs take swapfiles
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directly. btrfs needs `chattr +C` (NOCOW), no compression, and no
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snapshots in the swapfile path — check `df -T` before planning, or
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`mkswap` will reject the file.
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- **Renaming an *active* swapfile works (inode-based) but leaves a stale
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path in `/proc/swaps`** — swap it off first, then rename, then `swapon`
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(which is exactly what the step-3 consolidation does). Migration is
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observable while it runs: in the 2026-09-12 run `swapoff` of 4 GiB took
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65 s and used-RAM rose only ~3 GiB (pages touched during migration), the
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rest relocating on disk. If used-RAM climbs toward the whole swapped
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amount, let it finish rather than aborting.
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## Trash
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The previous 8 GiB `/swap.img` (dated 2026-07-21) is staged, not deleted, at
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`dankclaw:~/.AGENTTRASH/20260912-swapfile-8g/swap.img` (8.1 GiB). Purge
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only on explicit approval.
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## See Also
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- [[halogen-flash-server]] — the memory model that motivated this
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- [[Dankclaw System Specs]] — the Strix Halo box
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- [[Dankclaw Improvements]] — other host-level changes
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