feat(monitoring): add a disk health dashboard #667

2026-08-27T12:02:37Z

claude-bot commented

2026-08-27 12:02:37 +00:00

Durchsatz, IOPS, mittlere Operationslatenz, Auslastung, Queue-Tiefe und Controller-Temperatur für alle neun NVMe, dazu Cephs eigene OSD-Latenz als Gegenprobe zur Blockebene.

Jedes Panel joint auf Modell und Nodename statt auf den Gerätenamen. Das ist keine Kosmetik: nvme0 ist auf k8s-1 und k8s-3 die Kingston-Systemdisk, auf k8s-2 aber die Crucial. Eine Legende auf dem Gerätenamen vergleicht also unterschiedliche Hardware — und zwar lautlos. Die Inventar-Tabelle holt die OSD-Spalte aus ceph_disk_occupation, damit sie Rook folgt statt eine Geräteliste zu wiederholen, die beim nächsten Tausch veraltet.

Alle Abfragen wurden gegen Prometheus ausgeführt, bevor sie ins JSON kamen. Daraus stammen auch die Vorbehalte in den Panel-Beschreibungen: die Latenz ist akkumulierte Zeit durch abgeschlossene Operationen, also ein Mittelwert ohne Tail, und sie verschwindet im Leerlauf — Abwesenheit von Verkehr, nicht Abwesenheit eines Problems. Auslastung nahe 100 % bedeutet bei NVMe nicht Sättigung wie bei einer Spindel, deshalb teilt sich die Queue-Tiefe das Panel.

Zu #549, und der Befund ist schlechter als dort beschrieben. Temperatur ist der einzige SMART-nahe Wert, den es gibt, weil er als einziger über sysfs herauskommt; Verschleiß, geschriebene Datenmengen, Betriebsstunden und Medienfehler brauchen einen NVMe-Admin-ioctl, den hier kein Exporter absetzt. Das steht als eigenes Panel im Dashboard, damit ein grüner Bildschirm nicht als gesundes Laufwerk gelesen wird.

Wichtiger: die Crucial P3 wurden aus Ceph genommen, weil sie verschlissen waren, und tragen jetzt das EPHEMERAL-Volume. Die Laufwerke mit der geringsten Restlebensdauer halten also den Container-State — und genau die beobachtet nichts. Die gemessene Schreiblatenz trennt sie schon jetzt um mehr als eine Größenordnung von den Samsung-OSDs: 1–5 ms gegen 50–76 µs.

Nebenbei korrigiert: die Anleitung über dem Generator verlangte als dritten Schritt, eine Zeile in ../DASHBOARD-MIGRATION.md abzuhaken. Die Datei existiert nirgends im Repo, der Schritt war nicht befolgbar.

Refs #549

Durchsatz, IOPS, mittlere Operationslatenz, Auslastung, Queue-Tiefe und Controller-Temperatur für alle neun NVMe, dazu Cephs eigene OSD-Latenz als Gegenprobe zur Blockebene. **Jedes Panel joint auf Modell und Nodename statt auf den Gerätenamen.** Das ist keine Kosmetik: `nvme0` ist auf k8s-1 und k8s-3 die Kingston-Systemdisk, auf k8s-2 aber die Crucial. Eine Legende auf dem Gerätenamen vergleicht also unterschiedliche Hardware — und zwar lautlos. Die Inventar-Tabelle holt die OSD-Spalte aus `ceph_disk_occupation`, damit sie Rook folgt statt eine Geräteliste zu wiederholen, die beim nächsten Tausch veraltet. Alle Abfragen wurden gegen Prometheus ausgeführt, bevor sie ins JSON kamen. Daraus stammen auch die Vorbehalte in den Panel-Beschreibungen: die Latenz ist akkumulierte Zeit durch abgeschlossene Operationen, also ein Mittelwert ohne Tail, und sie verschwindet im Leerlauf — Abwesenheit von Verkehr, nicht Abwesenheit eines Problems. Auslastung nahe 100 % bedeutet bei NVMe nicht Sättigung wie bei einer Spindel, deshalb teilt sich die Queue-Tiefe das Panel. **Zu #549, und der Befund ist schlechter als dort beschrieben.** Temperatur ist der einzige SMART-nahe Wert, den es gibt, weil er als einziger über sysfs herauskommt; Verschleiß, geschriebene Datenmengen, Betriebsstunden und Medienfehler brauchen einen NVMe-Admin-ioctl, den hier kein Exporter absetzt. Das steht als eigenes Panel im Dashboard, damit ein grüner Bildschirm nicht als gesundes Laufwerk gelesen wird. Wichtiger: **die Crucial P3 wurden aus Ceph genommen, weil sie verschlissen waren, und tragen jetzt das EPHEMERAL-Volume.** Die Laufwerke mit der geringsten Restlebensdauer halten also den Container-State — und genau die beobachtet nichts. Die gemessene Schreiblatenz trennt sie schon jetzt um mehr als eine Größenordnung von den Samsung-OSDs: 1–5 ms gegen 50–76 µs. Nebenbei korrigiert: die Anleitung über dem Generator verlangte als dritten Schritt, eine Zeile in `../DASHBOARD-MIGRATION.md` abzuhaken. Die Datei existiert nirgends im Repo, der Schritt war nicht befolgbar. Refs #549

claude-bot added 1 commit 2026-08-27 12:02:38 +00:00

feat(monitoring): add a disk health dashboard

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d04b09310f

Throughput, IOPS, mean operation latency, utilisation, queue depth and
controller temperature for all nine NVMe drives, plus Ceph's own OSD latency for
comparison against the block layer.

Every panel joins node_disk_* to node_nvme_info and node_uname_info rather than
plotting the device name. That is not decoration: nvme0 is the Kingston system
disk on k8s-1 and k8s-3 and the Crucial on k8s-2, so a legend keyed on the
device compares different hardware across nodes and does so silently. The
inventory table resolves the OSD column through ceph_disk_occupation for the
same reason — it follows Rook instead of restating a device list that goes stale
the next time a drive is swapped.

Every expression was run against Prometheus before being written into the JSON,
which is also how the caveats in the panel descriptions were found. Latency is
accumulated-time over completed-operations, so it is a mean with no tail and it
vanishes while a device is idle: absence of traffic, not absence of a problem.
Utilisation near 100% on NVMe does not mean saturation the way it does on a
spindle, which is why queue depth shares that panel.

Temperature is the only SMART-adjacent value present, because it is the only one
the kernel publishes through sysfs. Wear, written-bytes totals, power-on hours
and media errors need an NVMe admin ioctl and no exporter here produces them
(#549). The dashboard says so in a panel rather than letting a green screen imply
a healthy drive.

That gap is worse than #549 describes, and the note records why. The Crucial P3
drives were retired from Ceph because they were worn, and now carry the
EPHEMERAL volume — so the drives with the least endurance left are the ones
holding container state, and they are the ones nothing watches. The measured
write latency already separates them from the Samsung OSDs by more than an order
of magnitude.

Also fixes the add-a-dashboard instructions above the generator, whose third
step told the reader to tick a row off ../DASHBOARD-MIGRATION.md. That file does
not exist anywhere in the repo, so the step could not be followed.

Refs #549

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

claude-bot referenced this pull request

2026-08-27 12:03:04 +00:00

No Prometheus metric exposes drive wear — endurance cannot be alerted on #549

k.renner merged commit 32dc191b18 into master

2026-08-27 12:06:02 +00:00

k.renner referenced this issue from a commit

2026-08-27 12:06:03 +00:00

Merge pull request 'feat(monitoring): add a disk health dashboard' (#667) from disk-dashboard into master

review-bot requested changes

2026-08-27 12:06:25 +00:00

review-bot left a comment

🤖 Automated review — model claude-sonnet-5 (complexity: normal), commit d04b09310f9e9b1b1f12a039345e7fffc2899f9c.

Advisory review by the review-bot pipeline. It never approves; a human merges. Push new commits to get a fresh review.

Summary

Adds a new Grafana "Disk Health" dashboard (kubernetes/apps/monitoring/dashboards/disk-health.json, 8 panels) plus the matching configMapGenerator entry, and fixes a stale step in the dashboards README comment (../DASHBOARD-MIGRATION.md, confirmed via find to not exist anywhere in the repo — the correction is accurate). The PromQL join pattern used throughout (label_replace(...) * on(instance[,nvmedev]) group_left(...) node_uname_info/node_nvme_info) matches the pre-existing convention already used in node-overview.json and infrastructure-overview.json, so it isn't a novel risk. There is one real discrepancy between what's described/promised and what the dashboard actually queries.

🔴 Blocking

kubernetes/apps/monitoring/dashboards/disk-health.json:12 (and PR body) — the promised "OSD column" doesn't exist in the query. The "Drive inventory" table panel's description says: "The OSD column comes from ceph_disk_occupation, so it follows Rook...", and the PR description repeats this as a headline feature ("Die Inventar-Tabelle holt die OSD-Spalte aus ceph_disk_occupation"). But the panel's only target (line 34) is:
```
node_nvme_info * on (instance) group_left(nodename) node_uname_info
```
There is no second query against ceph_disk_occupation, no group_left bringing in a ceph_daemon/OSD label, and no transformation step that would merge such a series in. Grepping the entire file for ceph_disk_occupation (grep -n ceph_disk_occupation disk-health.json) turns up only the description string itself — the metric is never actually queried. As shipped, the table can show device/model/serial/firmware/node but has no way to produce an OSD column at all. This is the dashboard's stated way of avoiding a "device list that goes stale," so its absence isn't cosmetic — the feature the PR is centered on isn't there. Needs either a second target joining ceph_disk_occupation (matched on node+device, since Ceph's device labels there are typically un-prefixed like nvme1n1) merged into the table via a merge/join transformation, or the description/PR text should be corrected to not claim it.

🟡 Suggestions

kubernetes/apps/monitoring/dashboards/disk-health.json:9 — the dashboard-level description states "Every panel joins node_disk_* to node_nvme_info and node_uname_info on purpose." This is only true of panels 2–6; panel 7 ("Ceph OSD latency") intentionally queries ceph_osd_apply_latency_ms/ceph_osd_commit_latency_ms directly (reasonably, since ceph_daemon already disambiguates), and panel 1 doesn't touch node_disk_* at all. Worth tightening the wording so it doesn't overstate the pattern's universality, especially since accuracy of these panel descriptions is the PR's explicit selling point.
kubernetes/apps/monitoring/dashboards/disk-health.json:73,106,139,177,183,210 — the nvmedev extraction regex "(nvme[0-9]+)n[0-9]+" assumes namespace suffix n[0-9]+ is always present on node_disk_* device labels, while node_nvme_info's own device label is matched with the bare "(nvme[0-9]+)". This matches the repo's stated intent (controller-level match, ignoring the namespace) and is consistent with the tested queries described in the PR body, but it's worth a one-time double check in Grafana's Explore view that no NVMe here exposes multiple namespaces (nvme0n1, nvme0n2, ...), since those would collapse onto the same nvmedev series in the throughput/IOPS/latency panels without a sum by/max by guard.

🟢 Nits

disk-health.json:266 uses schemaVersion: 39; every other dashboard in this directory except netbird-overview.json uses 38. Harmless (Grafana handles both), just a minor inconsistency if the repo intends to pin one Grafana schema version.
The "Gaps and caveats" text panel hard-codes model names (Kingston OM8PGP41024Q, Samsung PM983, Crucial P3) as prose, which is exactly the kind of hand-maintained inventory the dashboard elsewhere avoids by querying node_nvme_info live. Fine for a one-off explanatory note, just flagging the tension with the PR's own "device names are not identity" argument.

Tests

No tests exist for dashboard JSON anywhere else in this repo either (it's a GitOps config repo — dashboards are validated by the Grafana sidecar picking them up at runtime, not by CI), so the lack of tests here isn't a regression. The one thing that would have caught the blocking issue above is opening the dashboard against live Prometheus/Grafana and checking the "Drive inventory" table actually renders an OSD column — the PR body says all queries were run against Prometheus, but that check doesn't seem to have covered the specific claim about ceph_disk_occupation.

Recommendation

Request changes — 1 blocking issue (missing ceph_disk_occupation join in the "Drive inventory" table despite it being described, and advertised in the PR body, as a core feature).

🤖 **Automated review** — model `claude-sonnet-5` (complexity: normal), commit `d04b09310f9e9b1b1f12a039345e7fffc2899f9c`. > Advisory review by the `review-bot` pipeline. It never approves; a human merges. Push new commits to get a fresh review. --- ## Summary Adds a new Grafana "Disk Health" dashboard (`kubernetes/apps/monitoring/dashboards/disk-health.json`, 8 panels) plus the matching `configMapGenerator` entry, and fixes a stale step in the dashboards README comment (`../DASHBOARD-MIGRATION.md`, confirmed via `find` to not exist anywhere in the repo — the correction is accurate). The PromQL join pattern used throughout (`label_replace(...) * on(instance[,nvmedev]) group_left(...) node_uname_info/node_nvme_info`) matches the pre-existing convention already used in `node-overview.json` and `infrastructure-overview.json`, so it isn't a novel risk. There is one real discrepancy between what's described/promised and what the dashboard actually queries. ## 🔴 Blocking - **`kubernetes/apps/monitoring/dashboards/disk-health.json:12` (and PR body) — the promised "OSD column" doesn't exist in the query.** The "Drive inventory" table panel's `description` says: *"The OSD column comes from `ceph_disk_occupation`, so it follows Rook..."*, and the PR description repeats this as a headline feature ("Die Inventar-Tabelle holt die OSD-Spalte aus `ceph_disk_occupation`"). But the panel's only target (line 34) is: ``` node_nvme_info * on (instance) group_left(nodename) node_uname_info ``` There is no second query against `ceph_disk_occupation`, no `group_left` bringing in a `ceph_daemon`/OSD label, and no transformation step that would merge such a series in. Grepping the entire file for `ceph_disk_occupation` (`grep -n ceph_disk_occupation disk-health.json`) turns up only the description string itself — the metric is never actually queried. As shipped, the table can show device/model/serial/firmware/node but has no way to produce an OSD column at all. This is the dashboard's stated way of avoiding a "device list that goes stale," so its absence isn't cosmetic — the feature the PR is centered on isn't there. Needs either a second target joining `ceph_disk_occupation` (matched on node+device, since Ceph's device labels there are typically un-prefixed like `nvme1n1`) merged into the table via a `merge`/`join` transformation, or the description/PR text should be corrected to not claim it. ## 🟡 Suggestions - **`kubernetes/apps/monitoring/dashboards/disk-health.json:9`** — the dashboard-level description states "Every panel joins node_disk_* to node_nvme_info and node_uname_info on purpose." This is only true of panels 2–6; panel 7 ("Ceph OSD latency") intentionally queries `ceph_osd_apply_latency_ms`/`ceph_osd_commit_latency_ms` directly (reasonably, since `ceph_daemon` already disambiguates), and panel 1 doesn't touch `node_disk_*` at all. Worth tightening the wording so it doesn't overstate the pattern's universality, especially since accuracy of these panel descriptions is the PR's explicit selling point. - **`kubernetes/apps/monitoring/dashboards/disk-health.json:73,106,139,177,183,210`** — the `nvmedev` extraction regex `"(nvme[0-9]+)n[0-9]+"` assumes namespace suffix `n[0-9]+` is always present on `node_disk_*` device labels, while `node_nvme_info`'s own `device` label is matched with the bare `"(nvme[0-9]+)"`. This matches the repo's stated intent (controller-level match, ignoring the namespace) and is consistent with the tested queries described in the PR body, but it's worth a one-time double check in Grafana's Explore view that no NVMe here exposes multiple namespaces (`nvme0n1`, `nvme0n2`, ...), since those would collapse onto the same `nvmedev` series in the throughput/IOPS/latency panels without a `sum by`/`max by` guard. ## 🟢 Nits - `disk-health.json:266` uses `schemaVersion: 39`; every other dashboard in this directory except `netbird-overview.json` uses `38`. Harmless (Grafana handles both), just a minor inconsistency if the repo intends to pin one Grafana schema version. - The "Gaps and caveats" text panel hard-codes model names (Kingston OM8PGP41024Q, Samsung PM983, Crucial P3) as prose, which is exactly the kind of hand-maintained inventory the dashboard elsewhere avoids by querying `node_nvme_info` live. Fine for a one-off explanatory note, just flagging the tension with the PR's own "device names are not identity" argument. ## Tests No tests exist for dashboard JSON anywhere else in this repo either (it's a GitOps config repo — dashboards are validated by the Grafana sidecar picking them up at runtime, not by CI), so the lack of tests here isn't a regression. The one thing that would have caught the blocking issue above is opening the dashboard against live Prometheus/Grafana and checking the "Drive inventory" table actually renders an OSD column — the PR body says all queries were run against Prometheus, but that check doesn't seem to have covered the specific claim about `ceph_disk_occupation`. ## Recommendation Request changes — 1 blocking issue (missing `ceph_disk_occupation` join in the "Drive inventory" table despite it being described, and advertised in the PR body, as a core feature).

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Reference: konairius/homelab#667