docs: add disk usage estimation section to disk-requirements-and-retention#22071
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1 issue found across 1 file
Confidence score: 5/5
- Minor docs-only issue: the worked example in
docs/netdata-agent/sizing-netdata-agents/disk-requirements-and-retention.mdmixes GB and GiB, which could slightly confuse readers about sizing. - Low-severity, high-confidence documentation discrepancy with no code impact keeps merge risk minimal.
- Pay close attention to
docs/netdata-agent/sizing-netdata-agents/disk-requirements-and-retention.md- correct the GB vs GiB conversion in the example.
Prompt for AI agents (unresolved issues)
Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.
<file name="docs/netdata-agent/sizing-netdata-agents/disk-requirements-and-retention.md">
<violation number="1" location="docs/netdata-agent/sizing-netdata-agents/disk-requirements-and-retention.md:76">
P2: The worked example mixes GB and GiB units: 15,552,000,000 bytes is about 14.5 GiB, not 15.6 GiB.</violation>
</file>
Architecture diagram
sequenceDiagram
participant App as External System / Collector
participant Agent as Netdata Agent
participant DB as DBEngine (Multi-tier)
participant SQLite as Metadata Store (SQLite)
participant Disk as Persistent Storage
Note over App,Disk: Runtime Data Flow & Retention Logic
App->>Agent: Ingest metrics (metrics_per_second)
Agent->>DB: NEW: Store Tier 0 samples
Note right of DB: Cost: 0.6 bytes / sample
Agent->>DB: NEW: Store Tier 1 samples (Downsampled)
Note right of DB: Cost: 6 bytes / sample
Agent->>DB: NEW: Store Tier 2 samples (Downsampled)
Note right of DB: Cost: 18 bytes / sample
Agent->>SQLite: NEW: Update metadata & alert transitions
Note right of SQLite: Constant Overhead: ~1 GiB
loop For each Tier
DB->>Disk: Commit compressed data blocks
alt Retention logic (retention_seconds reached)
DB->>Disk: Reclaim space (FIFO / Page deletion)
else Storage within limits
DB->>Disk: Append new data
end
end
Note over Agent,Disk: Total Disk = (Tier Sums) + 1 GiB Metadata
Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.
| For a system collecting **10,000 metrics per second** with a **30-day retention** for `tier0`: | ||
|
|
||
| 1. Calculate seconds in 30 days: 30 days × 24 hours × 60 minutes × 60 seconds = **2,592,000 seconds** | ||
| 2. Apply the formula: 10,000 × 2,592,000 × 0.6 = **15,552,000,000 bytes** ≈ **15.6 GiB** |
Contributor
There was a problem hiding this comment.
P2: The worked example mixes GB and GiB units: 15,552,000,000 bytes is about 14.5 GiB, not 15.6 GiB.
Prompt for AI agents
Check if this issue is valid — if so, understand the root cause and fix it. At docs/netdata-agent/sizing-netdata-agents/disk-requirements-and-retention.md, line 76:
<comment>The worked example mixes GB and GiB units: 15,552,000,000 bytes is about 14.5 GiB, not 15.6 GiB.</comment>
<file context>
@@ -49,6 +49,40 @@ In practice, with default settings and an ingestion rate of about 4,000 metrics
+For a system collecting **10,000 metrics per second** with a **30-day retention** for `tier0`:
+
+1. Calculate seconds in 30 days: 30 days × 24 hours × 60 minutes × 60 seconds = **2,592,000 seconds**
+2. Apply the formula: 10,000 × 2,592,000 × 0.6 = **15,552,000,000 bytes** ≈ **15.6 GiB**
+
+:::note
</file context>
Suggested change
| 2. Apply the formula: 10,000 × 2,592,000 × 0.6 = **15,552,000,000 bytes** ≈ **15.6 GiB** | |
| 2. Apply the formula: 10,000 × 2,592,000 × 0.6 = **15,552,000,000 bytes** ≈ **14.5 GiB** |
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Summary
This PR adds a new "Estimating Disk Usage" section to the disk-requirements-and-retention documentation, providing users with a clear formula and worked example to calculate their own database size requirements.
Changes
Disk per tier (bytes) = metrics_per_second × retention_seconds × bytes_per_sampleAudit Context
Session Query: how does one estimate the database usage by netdata
Decision Verdict: surgical_edit
The validation identified that while most information about database sizing was accurate, the documentation lacked a clear formula and calculation guidance for users to estimate their own disk requirements. This PR addresses that gap by providing a structured approach with practical examples.
Checklist
Summary by cubic
Adds an “Estimating Disk Usage” section to the disk requirements doc with a simple formula and a worked example to size Netdata storage per tier. Includes a bytes-per-sample table (tier0 0.6, tier1 6, tier2 18) and notes ~1 GiB overhead for SQLite/metadata.
Written for commit e10af99. Summary will update on new commits.