pulse/docs/METRICS_HISTORY.md

Metrics History (Persistent)

Pulse persists metrics history to disk so trend views and sparklines survive restarts.

Storage Location

Metrics history is stored in a SQLite database named metrics.db under the Pulse data directory:

• systemd/LXC installs: typically /etc/pulse/metrics.db
• Docker/Kubernetes installs: typically /data/metrics.db

Retention Model (Tiered)

Pulse keeps multiple resolutions of the same data, which allows longer history without storing raw samples forever:

• Raw (high-resolution, short window)
• Minute aggregates
• Hourly aggregates
• Daily aggregates

Default retention values (subject to change) are:

• Raw: 2 hours
• Minute: 24 hours
• Hourly: 7 days
• Daily: 90 days
• Rollups: every 15 minutes by default, bounded so rollups still run well before raw samples expire

Advanced: Retention Tuning

Tiered retention is stored in system.json in the Pulse data directory:

• systemd/LXC installs: typically /etc/pulse/system.json
• Docker/Kubernetes installs: typically /data/system.json

Keys:

{
  "metricsRetentionRawHours": 2,
  "metricsRetentionMinuteHours": 24,
  "metricsRetentionHourlyDays": 7,
  "metricsRetentionDailyDays": 90
}

After changing these values, restart Pulse.

Advanced: Disk Write Tuning

Pulse keeps metrics history on disk by default. SSD-sensitive installs can move only the metrics SQLite database without moving secrets or general config:

PULSE_METRICS_DB_PATH=/dev/shm/pulse/metrics.db

Use a dedicated directory owned by the account running Pulse. Do not place the database directly in a shared parent such as /tmp/metrics.db: Pulse secures the database directory to mode 0700 and will reject a directory owned by another user. On systemd installs, PrivateTmp=true also means a path below /tmp is private to the service and will not appear in the host's /tmp.

The default systemd sandbox permits /dev/shm/pulse and Pulse can create that subdirectory itself. A dedicated mount elsewhere, such as /mnt/ramdisk, also needs an explicit writable-path grant:

sudo install -d -o pulse -g pulse -m 0700 /mnt/ramdisk/pulse
sudo systemctl edit pulse

Add this drop-in (replace pulse with the installed unit name if different):

[Service]
ReadWritePaths=/mnt/ramdisk/pulse

Then set PULSE_METRICS_DB_PATH=/mnt/ramdisk/pulse/metrics.db in /etc/pulse/.env and restart Pulse. ProtectSystem=strict deliberately keeps paths outside the unit's writable allowlist read-only even when Unix ownership would otherwise permit writes.

For Docker, mount a tmpfs at the selected directory and keep /data on a persistent volume:

services:
  pulse:
    environment:
      PULSE_METRICS_DB_PATH: /metrics-tmpfs/metrics.db
    tmpfs:
      - /metrics-tmpfs:size=512m,uid=1000,gid=1000,mode=0700

Using tmpfs makes metrics history ephemeral across restarts. It should not be used for /data, because /data also contains config, encrypted credentials, tokens, and other state that must remain durable.

The aggregation cadence can also be lengthened when an install prefers fewer, larger rollup writes over more frequent smaller writes:

PULSE_METRICS_ROLLUP_INTERVAL=30m

Values below 5 minutes are ignored. Values longer than half of the raw-retention window are capped by the metrics store so raw samples are still rolled up before retention pruning can remove them.

API Access

Pulse exposes the persistent metrics store via:

• GET /api/metrics-store/stats
• GET /api/metrics-store/history

These endpoints require authentication with the monitoring:read scope.

History Query Parameters

GET /api/metrics-store/history supports:

• resourceType (required): node, vm, container, storage, dockerHost, dockerContainer
• resourceId (required): resource identifier (for guests use instance:node:vmid)
• metric (optional): cpu, memory, disk, etc. Omit to return all metrics for the resource.
• range (optional): 1h, 6h, 12h, 24h, 1d, 7d, 30d, 90d (default 24h; duration strings also accepted)
• maxPoints (optional): Downsample to a target number of points

Example:

curl -H "X-API-Token: $TOKEN" \
  "http://localhost:7655/api/metrics-store/history?resourceType=vm&resourceId=pve1:node1:100&range=7d&metric=cpu"

License: Requests beyond Community's 7d floor require the paid long_term_metrics entitlement. Relay unlocks 14d, Pro and legacy Pro+ unlock 90d, and requests beyond the active tier's limit return 402 Payment Required. Aliases: guest (VM/LXC) and docker (Docker container) are accepted, but persistent store data uses the canonical types above.

Troubleshooting

• No sparklines / empty history: confirm the instance can write to the data directory and that metrics.db exists.
• Large disk usage: reduce polling frequency first. If you need tighter retention, adjust the tiered retention settings in system.json (advanced) and restart Pulse.