SIEM Security Log Storage, EPS & Audit Retention Calculator
Calculate aggregate Events Per Second (EPS), daily raw log volume, indexed Hot Storage, and compressed Cold Archive capacity for Wazuh & Elastic SIEM.
Input Parameters
Calculation Results
- Total Monitored Log Sources
- 35 Nodes
- Aggregate Log Ingestion Rate (EPS)
- 525 EPS
- Estimated Peak Burst Rate (2.5× EPS)
- 1,313 EPS
- Total Log Events per Day
- 45.36 Million Events
- Daily Raw Log Volume
- 15.88 GB/Day
- Daily Indexed Hot Volume (+10% Index)
- 17.47 GB/Day
- Required Hot Tier Storage (NVMe)
- 0.524 TB
- Required Cold Archive Storage (Compressed)
- 1.064 TB
- Total Recommended Disk (+20% Watermark Buffer)
- 1.906 TB
- Recommended Disk Write IOPS
- 225 IOPS
- Collector Network Ingest Bandwidth
- 1.47 Mbps
Validate firewall rulesets and cron timers in staging before production rollout.
| Storage Tier | Retention Duration (Days) | Storage & Indexing Format | Required Capacity (TB) |
|---|---|---|---|
| Hot Tier (NVMe Indexed Search / SIEM Aktif) | 30 Days | Indexed JSON + Lucene (1.1× raw) | 0.524 TB |
| Cold Archive Tier (Object Storage / Zstd / Gzip) | 335 Days | Compressed Archive (5:1) | 1.064 TB |
| Total + Safety Buffer Watermark (20%) | 365 Days | Total Kapasitas Disk Direkomendasikan | 1.906 TB |
Technical Accuracy Note: Calculation results are engineering estimates based on standard RFC/IEEE/ITU-T models. Actual field performance may vary due to protocol overhead, hardware specifications, and environmental factors.
How to Use This Tool
- Enter the number of monitored network appliances/firewalls and servers, along with the average Events Per Second (EPS) per device and bytes per log event.
- Set the Hot Storage retention window (indexed real-time search, in days) and Cold Archive retention duration along with the archive compression ratio.
- Review the aggregate EPS, daily raw volume (GB/day), Hot and Cold storage requirements (TB), total disk capacity with a 20% safety buffer, and target write IOPS.
Worked Example: Mid-Size Wazuh/ELK Cluster (35 Log Sources, 1-Year Retention)
Worked example: 10 network devices + 25 servers (35 sources total) at 15 EPS and 350 bytes/event generate 525 EPS (15.88 GB/day). A 30-day Hot + 335-day Cold retention policy (5:1 compression) requires 3.109 TB total disk (with 20% buffer).
- Network Appliances & Firewalls Count
- 10
- Production Servers & Endpoints Count
- 25
- Average Events Per Second (EPS) per Device
- 15 EPS
- Average Size per Log Event (Bytes)
- 350 Byte
- Indexed Hot Storage Retention (Days)
- 30 Hari
- Compressed Cold Archive Retention (Days)
- 335 Hari
- Cold Archive Compression Ratio (e.g. 5 for 5:1)
- 5
- Total Monitored Log Sources
- 35 Nodes
- Aggregate Log Ingestion Rate (EPS)
- 525 EPS
- Estimated Peak Burst Rate (2.5× EPS)
- 1,313 EPS
- Total Log Events per Day
- 45.36 Million Events
- Daily Raw Log Volume
- 15.88 GB/Day
- Daily Indexed Hot Volume (+10% Index)
- 17.47 GB/Day
- Required Hot Tier Storage (NVMe)
- 0.524 TB
- Required Cold Archive Storage (Compressed)
- 1.064 TB
- Total Recommended Disk (+20% Watermark Buffer)
- 1.906 TB
- Recommended Disk Write IOPS
- 225 IOPS
- Collector Network Ingest Bandwidth
- 1.47 Mbps
| Storage Tier | Retention Duration (Days) | Storage & Indexing Format | Required Capacity (TB) |
|---|---|---|---|
| Hot Tier (NVMe Indexed Search / SIEM Aktif) | 30 Days | Indexed JSON + Lucene (1.1× raw) | 0.524 TB |
| Cold Archive Tier (Object Storage / Zstd / Gzip) | 335 Days | Compressed Archive (5:1) | 1.064 TB |
| Total + Safety Buffer Watermark (20%) | 365 Days | Total Kapasitas Disk Direkomendasikan | 1.906 TB |
Core Concept & Engineering Notes
How It Was Calculated (Formulas & Steps)
Mathematical Formulas
- Total EPS = (Network_Devices + Servers) × Average_EPS_per_Node
- Daily Raw Log Volume (GB/day) = (Total_EPS × 86,400 seconds × Bytes_per_Event) ÷ 10^9
- Hot Storage Capacity (TB) = (Daily_Raw_GB × 1.1 Index_Overhead × Hot_Days) ÷ 1,000
- Cold Archive Capacity (TB) = ((Daily_Raw_GB ÷ Compression_Ratio) × Cold_Days) ÷ 1,000
Step-by-Step Calculation
- Total Sumber Log = 10 perangkat jaringan + 25 server = 35 node.
- Total Events Per Second (EPS) = 35 × 15 EPS = 525 EPS (Estimasi Puncak 2.5× = 1313 EPS).
- Volume Log Mentah Harian = 525 EPS × 86.400 detik × 350 byte = 15.88 GB/hari (45.36 juta event/hari).
- Kebutuhan Hot Storage (30 hari × 17.47 GB/hari termasuk indeks 1.1×) = 0.524 TB.
- Kebutuhan Cold Archive (335 hari ÷ rasio kompresi 5:1) = 1.064 TB.
- Total Disk dengan Safety Buffer 20% = (0.524 + 1.064) × 1,2 = 1.906 TB.
Frequently Asked Questions (FAQ)
Why do Elasticsearch and Wazuh Indexer require 15%–20% free disk space at all times?
Elasticsearch enforces disk allocation watermarks at 85%–95% utilization. Once disk usage crosses the flood-stage watermark, indices are automatically locked into read-only mode to prevent shard corruption.
What is a typical EPS rate for a production Linux server or enterprise firewall?
A quiet Linux application server emits 2–10 EPS, busy web or database nodes generate 20–50 EPS, while perimeter firewalls logging per-session NAT translations and denied packets often emit 50 to 500+ EPS.
What is a realistic compression ratio for cold-archived JSON and Syslog text files?
Because log files contain highly repetitive textual tokens (timestamps, hostnames, IP prefixes, and JSON keys), gzip and zstd routinely achieve 5:1 (80% reduction) to 8:1 compression ratios.
What log retention durations are required by ISO 27001 and PCI-DSS standards?
PCI-DSS Requirement 10.7 and common ISO 27001 audit baselines mandate retaining audit trail history for at least 1 year (365 days), with a minimum of 90 days immediately searchable online.
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References & Notes
- NIST Special Publication 800-92 — Guide to Computer Security Log Management
- Wazuh Documentation — Hardware & Storage Sizing Requirements for Indexer Nodes
Note: Results above are mathematical estimates based on standard formulas. Always verify against official vendor documentation and site conditions before production deployment.
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Engineering Sensitivity Analysis, Response Curve & Technical Citation
1. 1. 3-Point Engineering Sensitivity & Tolerance Envelope
Comparative evaluation across theoretical laboratory bounds (0% loss), current nominal operating point, and conservative field safety bounds (±15% thermal/aging derating).
| Evaluated Parameter | Ideal Theoretical Bound | Nominal Operating Point | Conservative Safety Bound (±15%) | Engineering Derating Rule |
|---|---|---|---|---|
| Total Monitored Log Sources | 31.5 | 35 | 40.25 | Engineering Safety Margin (+15% Overhead) |
| Aggregate Log Ingestion Rate (EPS) | 473 | 525 | 604 | Engineering Safety Margin (+15% Overhead) |
| Estimated Peak Burst Rate (2.5× EPS) | 1,182 | 1,313 | 1,510 | Engineering Safety Margin (+15% Overhead) |
| Total Log Events per Day | 40.82 | 45.36 | 52.16 | Engineering Safety Margin (+15% Overhead) |
| Daily Raw Log Volume | 14.29 | 15.88 | 18.26 | Engineering Safety Margin (+15% Overhead) |
2. 2. Mathematical Function Curve & Operating Coordinate (x₀, y₀)
3. 3. Physical Constants & Normative Standard Clauses
Offline Multi-GPU Cluster Hash Rate Benchmark
Section 5.1.1.2 Memorized Secret Verifiers — Order-of-magnitude 10¹¹ guesses/sec benchmark for evaluating lower-bound password entropy resistance against offline attacks.
Decimal Terabyte (SI) to Binary Tebibyte (IEC) Conversion Ratio
Clause 4 — Binary Prefixes — 1 TB = 10¹² Bytes; 1 TiB = 2⁴⁰ Bytes = 1,099,511,627,776 Bytes.
4. 4. Independent Technical & Academic Citation (IEEE / APA 7th / BibTeX / LaTeX)
Use the standard citation formats below to reference this computational methodology in engineering specifications, audit reports, or academic papers.
[IEEE] KalkuNet Engineering Team, "SIEM Security Log Storage, EPS & Audit Retention Calculator — Standard Engineering Computational Instrument," KalkuNet Technical Suite, 2026. [Online]. Available: https://kalkunet.com/en/tools/security-log-storage-calculator. [Accessed: 2026-11-08].
[APA 7th] KalkuNet Engineering Team. (2026). SIEM Security Log Storage, EPS & Audit Retention Calculator (Production release 2026-11-08) [Engineering computational software]. KalkuNet. https://kalkunet.com/en/tools/security-log-storage-calculator
@software{kalkunet_security_log_storage_calculator_2026,
author = {{KalkuNet Engineering Team}},
title = {{SIEM Security Log Storage, EPS & Audit Retention Calculator --- KalkuNet Engineering Suite}},
year = {2026},
publisher = {KalkuNet.com},
url = {https://kalkunet.com/en/tools/security-log-storage-calculator},
urldate = {2026-11-08}
}
% LaTeX Engineering Derivation — Generated via https://kalkunet.com/en/tools/security-log-storage-calculator
\begin{equation}
\text{Model: } Total EPS = (Network_Devices + Servers) × Average_EPS_per_Node
\end{equation}
% Parameter Input Terukur: networkDevicesCount = 10, \; serversCount = 25, \; avgEpsPerDevice = 15, \; avgBytesPerEvent = 350
% Hasil Evaluasi Numerik : totalLogSources = \mathbf{35}, \; totalEps = \mathbf{525}, \; peakEpsEstimated = \mathbf{1313}