Service Level Objectives — VayuPress

Version: 1.0
Last reviewed: 2026-06-13
Authority: VayuPress Maintainers

SLO Definitions

SLO Name	Target	Window	Error Budget	Measurement
`signing.latency.p95`	99.9%	30 days	43.2 min/month	P95 of `signing.Sign()` calls ≤ 100ms
`plugin.invocation.success`	99.0%	7 days	1.68 hr/week	Plugin `Invoke()` returns nil error
`federation.inbox.lag`	95.0%	24 hours	72 min/day	Inbox activity processed within 60s of receipt
`restore.rto.10min`	100%	365 days	0 min/year	Restore-from-backup completes within 10 minutes
`wal.recovery.success`	99.9%	30 days	43.2 min/month	WAL recovery succeeds without data loss

Error Budget Policy

When an error budget reaches ≤ 20% remaining:

Engineering work on new features pauses.
Focus shifts to reliability improvements.
Incident post-mortem required within 48 hours.

When an error budget reaches 0%:

All feature work stops.
P0 incident declared.
Release gate blocked until budget recovers.

SLO Instrumentation

SLOs are tracked via internal/slo package:

tr := slo.Global.Register(slo.SLOSigningP95)
// On each signing call:
tr.Record(err == nil)
// Check budget:
if tr.BudgetExhausted() {
    logging.LogJSON(logging.LogFields{Level: "error", Component: "slo", Msg: tr.Status()})
}

Latency Targets

Operation	P50 target	P95 target	P99 target
`signing.Sign()`	≤ 10ms	≤ 100ms	≤ 500ms
`signing.Verify()`	≤ 20ms	≤ 150ms	≤ 500ms
`merkle.New(1024)`	≤ 1ms	≤ 5ms	≤ 20ms
HTTP article GET	≤ 50ms	≤ 200ms	≤ 1s
Plugin hook invocation	≤ 100ms	≤ 500ms	≤ Manifest.Timeout
DB read (indexed)	≤ 1ms	≤ 10ms	≤ 50ms
DB write (WAL)	≤ 5ms	≤ 50ms	≤ 200ms

Recovery Objectives

Scenario	RTO	RPO	Runbook
WAL corruption	30 min	Last backup (≤ 24h)	wal-corruption-recovery.md
Process crash	< 1 min	0 (SQLite WAL persists)	Systemd auto-restart
Full server loss	< 10 min	Last backup (≤ 24h)	backup-restore.md
Plugin quarantine storm	< 5 min	0	incident-response.md
Signing key compromise	< 1 hour	0 (re-sign from archive)	signing-model.md

Benchmark Thresholds (CI-enforced)

From testdata/bench/:

Benchmark	Baseline	Max regression
`BenchmarkSign`	~24µs/op	+20%
`BenchmarkVerify`	~52µs/op	+20%
`BenchmarkMerkleNew1024`	~406µs/op	+30%
`BenchmarkMerkleProof`	~948ns/op	+10%

Regressions exceeding these thresholds block the release gate.