From 66408ff68f638a53e76a3c1e987fc60894f61d38 Mon Sep 17 00:00:00 2001
From: Jane Alesi <ja@satware.ai>
Date: Thu, 2 Apr 2026 10:40:10 +0200
Subject: [PATCH] docs(tech): add pre-firmware-update NVMe benchmark (GXA7401Q)

Comprehensive benchmark of Samsung PM9A1 NVMe SSD before firmware
update from GXA7401Q to GXA7802Q. Includes SMART health, hdparm,
and fio results (seq/rand read/write, 4K blocks, iodepth=32).
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 docs/tech/nvme-benchmark-pre-gxa7802q.md | 113 +++++++++++++++++++++++
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+# NVMe Benchmark: Pre-Firmware Update (GXA7401Q)
+
+> **Date**: 2026-04-02 10:35 CET
+> **Device**: Samsung PM9A1 (MZVL2512HCJQ-00B00), 512GB
+> **Serial**: S675NF0R703667
+> **Firmware**: GXA7401Q (pre-update)
+> **OS**: Manjaro Linux, kernel 6.12, KDE 6.5.6
+> **NVMe slot**: /dev/nvme0n1 (root drive)
+
+## SMART Health Data
+
+| Metric | Value |
+|--------|-------|
+| Critical Warning | 0 (healthy) |
+| Temperature | 51°C (Sensor 2: 64°C) |
+| Available Spare | 100% |
+| Available Spare Threshold | 10% |
+| Percentage Used | 19% |
+| Data Units Read | 17.97 TB |
+| Data Units Written | 94.19 TB |
+| Host Read Commands | 683,328,216 |
+| Host Write Commands | 1,651,377,088 |
+| Controller Busy Time | 9,265 min |
+| Power Cycles | 884 |
+| Power On Hours | 4,926 h (~205 days) |
+| Unsafe Shutdowns | 88 |
+| Media Errors | 0 |
+| Error Log Entries | 0 |
+
+## hdparm Results
+
+| Test | Throughput |
+|------|-----------|
+| Cached Reads | 7,349.97 MB/sec |
+| Buffered Disk Reads | 741.99 MB/sec |
+
+## fio Benchmarks (4K block, libaio, iodepth=32, 30s per test)
+
+### Sequential Read
+
+| Metric | Value |
+|--------|-------|
+| Bandwidth | 1,554 MiB/s (1,630 MB/s) |
+| IOPS | 398,000 |
+| Avg Latency | 80.16 µs |
+| P99 Latency | 128 µs |
+| P99.9 Latency | 186 µs |
+
+### Sequential Write
+
+| Metric | Value |
+|--------|-------|
+| Bandwidth | 1,305 MiB/s (1,368 MB/s) |
+| IOPS | 334,000 |
+| Avg Latency | 95.53 µs |
+| P99 Latency | 163 µs |
+| P99.9 Latency | 255 µs |
+
+### Random Read
+
+| Metric | Value |
+|--------|-------|
+| Bandwidth | 1,409 MiB/s (1,477 MB/s) |
+| IOPS | 361,000 |
+| Avg Latency | 88.42 µs |
+| P99 Latency | 141 µs |
+| P99.9 Latency | 200 µs |
+
+### Random Write
+
+| Metric | Value |
+|--------|-------|
+| Bandwidth | 1,135 MiB/s (1,190 MB/s) |
+| IOPS | 291,000 |
+| Avg Latency | 109.78 µs |
+| P99 Latency | 190 µs |
+| P99.9 Latency | 334 µs |
+
+### Random Read/Write (70/30)
+
+| Metric | Read | Write |
+|--------|------|-------|
+| Bandwidth | 919 MiB/s (964 MB/s) | 394 MiB/s (413 MB/s) |
+| IOPS | 235,000 | 101,000 |
+| Avg Latency | 94.72 µs | 95.05 µs |
+| P99 Latency | 149 µs | 149 µs |
+
+## Test Configuration
+
+```text
+fio-3.41
+Block size: 4096B
+IO Engine: libaio
+IO Depth: 32
+Direct IO: yes
+Runtime: 30s per test
+File size: 1GiB
+Directory: /tmp (on NVMe root drive)
+```
+
+## Assessment
+
+- Drive health is good: 0 media errors, 0 error log entries, 100% spare
+- 19% endurance used after ~205 days powered on (within normal range)
+- Sequential performance consistent with PCIe 4.0 x4 NVMe expectations
+- Random IOPS strong for a client-grade TLC SSD
+- Temperature under load: 51-64°C (well within spec)
+
+## Next Steps
+
+- Apply firmware update to GXA7802Q
+- Re-run identical benchmarks post-update
+- Compare results in `docs/tech/nvme-benchmark-post-gxa7802q.md`
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