Add posts: RAID silent corruption + self-hosted mem0 (en/zh, og+banner)
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@@ -133,6 +133,44 @@ const BANNERS = {
],
},
'when-smart-says-healthy-but-your-raid-is-corrupting-data': {
titlebar: 'root@unraid — cache pool scrub',
lines: [
{ t: 'dim', text: 'btrfs RAID1 · 2× Samsung PM9A3 NVMe · same batch' },
{ t: 'prompt', text: '$' }, { t: 'cmd', text: 'btrfs scrub /mnt/cache' },
{ t: 'err', text: 'csum 0x8941f998 recurring = CRC32C(zero block)' },
{ t: 'prompt', text: '$' }, { t: 'cmd', text: 'self-heal rewrite → does NOT stick' },
{ t: 'err', text: 'write-path corruption · SMART stays clean' },
{ t: 'prompt', text: '$' }, { t: 'cmd', text: 'fix = restore VM + replace both drives' },
],
flow: [
{ n: '1', label: 'SMART clean' },
{ n: '2', label: 'csum zeros', err: true },
{ n: '3', label: 'self-heal no-stick' },
{ n: '4', label: 'restore VM' },
{ n: '5', label: 'replace both ✓' },
],
},
'self-hosting-mem0-memory-stack': {
titlebar: 'root@dsm — mem0 memory stack',
lines: [
{ t: 'prompt', text: '$' }, { t: 'cmd', text: "curl -X POST :20015/memories -H X-Api-Key" },
{ t: 'dim', text: 'user_id + text → mem0 extracts & stores' },
{ t: 'prompt', text: '¶' }, { t: 'ok', text: '→ remembers across sessions ✓' },
{ t: 'prompt', text: '$' }, { t: 'cmd', text: 'stack = mem0-api + LiteLLM + pgvector(pg17)' },
{ t: 'err', text: 'infer=true → LLM hop · slow writes' },
{ t: 'prompt', text: '' }, { t: 'ok', text: 'self-hosted · data stays on LAN ✓' },
],
flow: [
{ n: '1', label: 'POST /memories' },
{ n: '2', label: 'store fact' },
{ n: '3', label: 'search' },
{ n: '4', label: 'feed context' },
{ n: '5', label: 'remembers ✓' },
],
},
'hardening-a-tor-onion-service': {
titlebar: 'root@tor-host — onion service audit',
lines: [
+14 -4
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@@ -125,10 +125,20 @@ const TERMINALS = {
<div class="line"><span class="prompt">$</span><span class="cmd">warm session · 7s pacing · sweep.py</span><span class="fix">→ 20+ listings ✓</span></div>`,
'unraid-stop-array-hangs-on-swapfile': `
<div class="line"><span class="prompt">$</span><span class="cmd">unraid → stop array · swapfile on /mnt/cache</span></div>
<div class="line"><span class="prompt">&nbsp;</span><span class="err">umount: target is busy · /proc/swaps says /dev/loop0</span></div>
<div class="line"><span class="prompt">$</span><span class="cmd">swapoff -a + losetup -j at stopping_svcs</span><span class="fix">→ clean stop ✓</span></div>`,
};
<div class="line"><span class="prompt">$</span><span class="cmd">unraid → stop array · swapfile on /mnt/cache</span></div>
<div class="line"><span class="prompt">&nbsp;</span><span class="err">umount: target is busy · /proc/swaps says /dev/loop0</span></div>
<div class="line"><span class="prompt">$</span><span class="cmd">swapoff -a + losetup -j at stopping_svcs</span><span class="fix">→ clean stop ✓</span></div>`,
'when-smart-says-healthy-but-your-raid-is-corrupting-data': `
<div class="line"><span class="prompt">$</span><span class="cmd">scrub → re-read vdisk1.img</span></div>
<div class="line"><span class="prompt">&nbsp;</span><span class="err">csum 0x8941f998 = CRC32C(zeros) · recurring</span></div>
<div class="line"><span class="prompt">$</span><span class="cmd">self-heal rewrite does NOT stick</span><span class="fix">→ replace both drives ✓</span></div>`,
'self-hosting-mem0-memory-stack': `
<div class="line"><span class="prompt">$</span><span class="cmd">curl -X POST :20015/memories · X-Api-Key</span></div>
<div class="line"><span class="prompt">&nbsp;</span><span class="err">infer=true → LLM hop · slow write</span></div>
<div class="line"><span class="prompt">$</span><span class="cmd">infer=false · pgvector · LiteLLM gateway</span><span class="fix">→ remembers across chats ✓</span></div>`,
};
const DEFAULT_TERMINAL = `
<div class="line"><span class="prompt">$</span><span class="cmd">engineering · devops · self-hosting</span></div>
@@ -0,0 +1,192 @@
---
title: "How I Self-Hosted a Mem0 Memory Stack (So My AI Agent Remembers)"
description: "A private, self-hosted memory layer for AI agents — mem0 API + LiteLLM + PostgreSQL with pgvector on a Synology NAS. Semantic memory under your control, not a third party's."
pubDate: 2026-09-16
category: case-studies
tags: [mem0, docker, postgres, pgvector, litellm, ai, sharing]
ogImage: /og/self-hosting-mem0-memory-stack.png
banner: /banners/self-hosting-mem0-memory-stack.png
---
An AI agent that forgets everything between conversations is a tool you have
to reintroduce yourself to every session. My AI assistant (the one that runs
this very blog's workflow) used to start each chat from zero — until I gave it
a **memory layer**: a self-hosted [mem0](https://mem0.ai) stack that stores
facts it learns, retrieves them semantically, and survives across sessions.
This is the story of how I self-hosted it on my Synology NAS — private, fully
under my control, no data leaving my LAN.
## Why this matters
A memory layer changes what an agent can actually *do* for a business:
- **It stops re-answering the same questions.** Remember a customer's granted
trial, their product, their last support issue — and the next conversation
picks up where the last one ended.
- **It makes "personalization" real.** A bot that recalls your customer's
preferences and history is a bot that feels like a person. That's not
prompt-sugar; it's a stored, searchable record.
- **It keeps control of your data.** Every "memory" I dislike about hosted
memory services is solved by running the stack yourself — the facts live
in my own PostgreSQL, on my own NAS, behind my own network.
For anyone running AI agents (support bots, research assistants, personal
automation) the question isn't *should* the agent remember — it's whether the
memory is a private asset or a third party's.
## What mem0 does
Mem0 is "memory in a box" for LLM apps. Instead of you hand-rolling an
embeddings table and a similarity search, it gives you a small API that does
the three things memory needs:
1. **Add a memory**`POST /memories` with a fact or a conversation; it
extracts, dedupes, and stores it (optionally classified by an LLM).
2. **Search**`GET /search` with a query returns the most relevant stored
facts, ranked by semantic similarity.
3. **User scoping** — memories belong to a `user_id`, so you can keep memory
per customer, per project, or per conversation without cross-talk.
The "memory" is the extracted fact. The "retrieval" is vector similarity. You
get the agent even if you never touch a vector database yourself.
## The stack
Three containers on my Synology DS1821+, as a Portainer compose stack:
- **mem0 API** — the memory service itself (custom local build), listening
on port `20015`.
- **LiteLLM** — the LLM gateway in front of whatever model does the fact
extraction. I can swap the underlying model without touching mem0's config.
- **PostgreSQL 17 + pgvector** — the database. `pgvector/pgvector` bundles
Postgres with the vector extension as a first-class citizen, so semantic
search lives in the same DB as everything else.
```text
┌──────────────┐ /search & /memories ┌──────────────────┐
│ AI agent / │ ──── X-Api-Key + JSON ───────▶ │ mem0 API :20015 │
│ Hermes / bot │ └────────┬─────────┘
└──────────────┘ │ pgvector
PostgreSQL 17 + pgvector
┌──────────────┐ model calls (extract) ┌──────────────────┐
│ OpenAI etc. │ ◀───────── LiteLLM ──────────│ fact-classifier │
└──────────────┘ └──────────────────┘
```
A representative compose looks like this:
```yaml
services:
mem0-postgres:
image: pgvector/pgvector:pg17
environment:
POSTGRES_USER: mem0
POSTGRES_PASSWORD: ${MEM0_DB_PASSWORD}
POSTGRES_DB: mem0
volumes:
- ./data/pg:/var/lib/postgresql/data
restart: unless-stopped
mem0-litellm:
image: ghcr.io/berriai/litellm:main-stable
command: ["--config", "/app/config.yaml"]
volumes:
- ./litellm-config.yaml:/app/config.yaml
restart: unless-stopped
mem0-api:
build: ./mem0-api
environment:
OPENAI_API_KEY: ${OPENAI_API_KEY}
OPENAI_API_BASE: http://mem0-litellm:4000/v1 # go through the gateway
MEM0_API_KEY: ${MEM0_API_KEY} # X-Api-Key for /search & /memories
POSTGRES_URL: postgresql://mem0:${MEM0_DB_PASSWORD}@mem0-postgres/mem0
ports:
- "20015:8000"
restart: unless-stopped
```
(Mine is built from the mem0 repo with the model/fact-extraction directed
through LiteLLM; the exact image tag is me maintaining a local build, and I
keep the real API key out of the compose file — it's an env secret.)
## Using it
Once it's up, the API is refreshingly small. Add a fact (fast, verbatim):
```bash
curl -X POST http://192.168.1.1:20015/memories \
-H "Content-Type: application/json" \
-H "X-Api-Key: $MEM0_API_KEY" \
-d '{
"user_id": "customer-2211",
"text": "Customer 2211 prefers email over WhatsApp for order updates."
}'
```
Retrieve the most relevant memories later:
```bash
curl -X POST http://192.168.1.1:20015/memories/search \
-H "Content-Type: application/json" \
-H "X-Api-Key: $MEM0_API_KEY" \
-d '{
"user_id": "customer-2211",
"query": "how should I reach this customer?",
"limit": 5
}'
```
Then inject the returned facts into the agent's system prompt (or context)
before it answers. That's the whole loop: **store facts, retrieve what's
relevant, use it in the next reply.**
### The `infer` gotcha that cost me a day
- `POST /memories` with the **default `infer=true`** runs the LLM fact
extractor — it classifies and cleans each memory. That's smart but **slow**,
and every call costs a model round-trip.
- If I just want the agent to note something verbatim and fast (user said
"please call me Andy"), I pass **`infer=false`** — no LLM hop, near-instant
storage.
The route of my stack is `/search` and `/memories` **without a `/v1` prefix**
(an early wrapper that assumed `/v1` 404'd for a while), and auth is a plain
`X-Api-Key` header. Small details, but they cost me time to discover.
## What I'd do differently
- **Set `infer=false` for routine logging from day one.** Only run the LLM
extractor on the facts that matter; the default inference mode makes every
write pricey for no benefit on throwaway notes.
- **Treat the API key as a real secret.** It gets embedded in agent configs
and compose envs, so I keep it out of the compose file and inject it via
environment secrets.
- **Put the DB on a disk I trust.** Mem0 is only as durable as its Postgres.
I run it on my NAS's protected volumes, with a backup job — because a
memory layer that forgets is worse than none.
## The result
A private, self-hosted memory layer answered by two small HTTP calls. My
agent now remembers customers, preferences, and decisions across sessions —
and because the stack sits in my own PostgreSQL behind my own network, none
of that leaves my control.
If you run AI agents that keep forgetting their context, self-hosting mem0
is one of the highest-value, lowest-friction upgrades you can make — and you
can do it without sending your memory to someone else's database.
---
## Want a memory-enabled AI setup for your business?
I build and self-host AI agents, memory stacks, websites, and infrastructure
for businesses. If you'd like your assistant to actually *remember* your
customers — or you want to talk about hiring me — I'd love to help:
- 📱 **WhatsApp:** [+60 12-797 2969](https://wa.me/60127972969)
- 📧 **Email:** [[email protected]](mailto:[email protected])
- 🌐 **Website:** [hoelee.com](https://hoelee.com)
@@ -0,0 +1,170 @@
---
title: "When SMART Says Healthy and Your RAID Is Silently Corrupting Data"
description: "A btrfs RAID1 pool on two healthy-looking NVMe drives quietly corrupted a Windows VM. How I caught it, the checksum forensic that proved it, and why I replaced both drives."
pubDate: 2026-09-16
category: devops
tags: [unraid, btrfs, nvme, raid, storage, data-loss, troubleshooting]
ogImage: /og/when-smart-says-healthy-but-your-raid-is-corrupting-data.png
banner: /banners/when-smart-says-healthy-but-your-raid-is-corrupting-data.png
---
Every storage guide tells you the same thing: trust SMART, check the event
log, and believe your filesystem. My hardware disagreed. In September 2026 a
btrfs RAID1 pool — two mirrored enterprise NVMe drives that said **"healthy"**
in every tool I could run — was quietly feeding my Windows 11 VM all-zero
bytes. Not visibly failing. Silently corrupting.
This is the full story: how the corruption surfaced, the checksum that gave
it away, and why the answer was "replace both drives, don't trust SMART".
## Why this matters
A corrupting disk is the worst kind of storage failure because it's the
easiest to miss:
- **SMART looked perfect.** Zero media errors, ~100% spare, on drives rated
for heavy enterprise write loads.
- **The pool had redundancy.** btrfs RAID1 mirrored every block across two
drives. Redundancy means nothing when *both* members lie the same way.
- **The failure was silent.** No red warning in the Unraid array status, no
failing drive, no hardware event — just VM reads slowly returning garbage
until a backup restore became the only option.
If your data only gets corrupted when nothing looks wrong, "backup" is not
paranoia — it's the entire ballgame. This incident is why a testable,
verified restore beats any array status screen.
## The setup
- **unRaid 7.x** on an Intel i9-13900K, with a Windows 11 VM as the primary
workstation (GPU passed through).
- **Cache pool:** two **Samsung PM9A3 3.84 TB** NVMe drives in **btrfs RAID1**.
Both from the **same production batch** (same controller/firmware
revision, `GDC7702Q`).
- The Windows VM's virtual disks (`vdisk1.img`, `vdisk2.img`) lived on that
pool, in the `domains/` share — plus **Docker's data root**.
- The VM's vdisks were **not** `NOCOW` — so every read was validated against
a btrfs checksum. That setting ended up being the reason I caught it at all.
## The symptom
I started noticing cache reads were crawling, and host commands were stalling:
`cat`, reading `/proc/loadavg`, even `docker image ls` were timing out. The
corrupt NVMe was being hammered at **4575 MB/s of reads**, and every read
saturating the drive stalled the whole host's I/O. A `docker system prune`
that should have finished in seconds just hung.
Then the real problem surfaced: the Windows VM began throwing read errors and
data that came back was **wrong** — files that were full of zero bytes,
checksum failures in the guest, and ultimately an unbootable primary VM.
## The forensic: `csum 0x8941f998`
On btrfs, when a read fails verification the kernel logs a checksum mismatch
for the affected extent. The same value kept recurring:
```text
btrfs: checksum verify failed on <device> wanted 0x8941f998 found <other>
```
That specific value was the first real clue. **`0x8941f998` is the CRC32C of
a block of zeros.** It has to be — it came up every time, across unrelated
files and inodes. What was happening wasn't random bit rot; the drive was
returning **all-zero blocks**, consistently, and those zero-filled reads were
exactly what btrfs was failing to verify:
- Check the value: `crc32c` of a zero-filled extent matches `0x8941f998`.
- It's the same value again and again → reads were **deterministically**
producing empty data, not occasionally flipping bits.
Two VM vdisks were affected (`vdisk1.img` inode 2358574, `vdisk2.img` inode
2362817), which fit the picture: a storage layer was returning zeros instead
of the data it was asked to read.
## The tell: self-heal "fixes" that never stuck
btrfs RAID1 is supposed to be self-healing: read a bad block on one member,
reconstruct it from the mirror, and rewrite the good data back. But as I
scrubbed and re-read the same (still all-zero) data, it became clear the
**rewrites were not sticking**. Each rebuild "succeeded" and the very next
read of the same extent produced zeros again.
That's the critical distinction:
- A drive that only **fails to read** is a read problem — self-heal should
recover it from the mirror.
- **A drive that also accepts and silently stores garbage** is a *write* or
*controller* problem — the mirror can't save you, because both paths agree
on the wrong answer.
When self-heal rewrites keep not sticking, you're no longer in "one bad
sector" territory. You're in "the device is lying about writes" territory,
and RAID redundancy won't help.
## Why both drives had to go
The data pointed at a **hardware defect in the same-batch drives**, not a
wear or one-off event:
- SMART was clean (0 media errors, ~100% spare, and `nvme0` had written
roughly 586 TiB — heavy, but on a drive rated for enterprise workloads).
- The two drives were **same-batch, same controller/firmware** (`GDC7702Q`).
- Corruption hit **both** RAID1 members in correlated fashion — the whole
point of mirroring (survive one drive dying) failed because both were dying
the same way, in lockstep.
With a correlated, batch-level defect, keeping one "healthy-looking" drive as
the surviving member is a false economy. **I restored the Windows VM from
backup and replaced both drives.**
## What I did in parallel: move the data off that pool
Before the drives were replaced, anything still worth reading had to come off
the failing pool — and it had to be **verified**, not assumed:
- **Docker's data root** moved off the cache: `docker` was relocated to
`/mnt/user/docker` (on `disk1`, overlay2). The whole tree was verified by
matching **path, size, and mtime** for all **3,997,569 files** against a
byte-comparison.
- The cache's `isos/`, `system/`, and `swapfile` moved to `disk1`; the
`isos/` set (~13 GB) was checked with `diff -rq`**EXIT=0**, no
differences.
- Everything moved was compared against the source **before** the cache copy
was deleted — never delete a copy you haven't verified.
The read-side corruption (all-zero blocks) and the write-side corruption
(self-heal not sticking) meant I trusted nothing from that pool without a
mirror, a checksum, or a fresh backup to compare against.
## What I'd do differently
1. **Test-restore the VM backup before needing it.** I'd verified backups
existed, but a corruption incident is not the time to first learn your
restore procedure. A scheduled test-restore catches both backup failure
*and* silent storage corruption.
2. **Treat same-batch drives as one drive.** Both PM9A3s came from the same
batch with the same firmware. For a married cache pool (or any RAID1)
that's a correlated-failure risk — prefer drives of different production
batches or at least hammer-test the pair before trusting a mirror.
3. **Detect, don't just hope.** btrfs checksums are what surfaced this
through the noise. The `NOCOW`-less vdisk config meant the filesystem was
validating every read; a pool of checksummed data is the difference
between "caught it and restored" and "shipped corrupted files for months".
4. **Don't trust SMART for flash.** For a healthy-looking NVMe that still
corrupts, the event count says nothing — the firmware-level defect can be
invisible to every SMART attribute.
## The result
One Windows VM restored from backup, both confirmed-failing drives replaced,
and Docker's data root safely off the pool. The cost was a few days of noise
and a rescue effort — but it was contained because the corruption was caught
by checksums, not wallowed in for weeks.
The lesson that sticks: **with storage, "redundant" is only as good as your
least-trustworthy member.** Two disks that fail together are not a mirror —
they're a single point of failure wearing two serial numbers. Verify your
restores, checksum your data, and when a drive's *rewards* of zeros keep
reappearing, replace the whole set.
---
@@ -0,0 +1,146 @@
---
title: "我如何在自家 NAS 上自托管 Mem0 记忆栈(让 AI 助手有记忆)"
description: "一套私有、自托管的 AI 助手记忆层——mem0 API + LiteLLM + PostgreSQL/pgvector,跑在 Synology NAS 上。语义记忆由你掌控,而不是第三方手里。"
pubDate: 2026-09-16
category: case-studies
tags: [mem0, docker, postgres, pgvector, litellm, ai, sharing]
ogImage: /og/self-hosting-mem0-memory-stack.png
banner: /banners/self-hosting-mem0-memory-stack.png
---
一个每次对话后都忘光一切的 AI 助手,就是一个每轮都要你重新自我介绍的工具。我的 AI 助手(就是驱动这个博客工作流的那个)曾经每场会话都从零开始——直到我给它加了一层**记忆**:一套自托管的 [mem0](https://mem0.ai) 栈,负责存储它学到的事实、按语义检索、并跨会话存活。
这就是我在自家 Synology NAS 上自托管它的故事——私有、完全由我掌控、数据绝不离开我的局域网。
## 为什么这件事重要
记忆层改变的是一个助手真正能为企业做的事:
- **不再重复回答同样的问题。** 记住客户获批的试用、他买的产品、上次的售后问题——下一段对话从上一次结束的地方继续。
- **让「个性化」成真。** 一个记得客户偏好和历史记录的机器人,就是一个人。这不是提示词糖衣;这是一份存储的、可检索的记录。
- **把数据掌控权留在自己手里。** 我对托管式记忆服务不满的每一点,自托管都解决了——事实存在我自己的 PostgreSQL 里、我自己的 NAS 上、我自己网络的后面。
对任何跑 AI 助手(售后机器人、研究助手、个人自动化)的人来说,问题不是助手**要不要**记住——而是这份记忆是一份私有资产,还是第三方的数据。
## mem0 做了什么
Mem0 是给 LLM 应用用的「开箱即用的记忆」。你不用手搓嵌入表和相似度检索,它给一个小 API,把记忆需要的三件事都做了:
1. **加一条记忆** —— `POST /memories` 传一条事实或一段对话;它抽取、去重并存储(可选由 LLM 分类)。
2. **检索** —— `GET /search` 带一个 query,返回按语义相似度排序的相关事实。
3. **按用户隔离** —— 记忆归属 `user_id`,所以可以按客户、按项目、按会话分开,互不串扰。
「记忆」就是抽取出来的事实;「检索」就是向量相似度。哪怕你从没亲手碰过向量数据库,也能让助手有记忆。
## 技术栈
Synology DS1821+ 上用 Portainer compose 栈跑三个容器:
- **mem0 API** —— 记忆服务本身(本地自定义构建),监听 `20015` 端口。
- **LiteLLM** —— 真正做事实抽取的模型前面的 LLM 网关。不碰 mem0 配置就能换底层模型。
- **PostgreSQL 17 + pgvector** —— 数据库。`pgvector/pgvector` 把 Postgres 和向量扩展打包成一等公民,语义搜索和别的一切同库。
```text
┌──────────────┐ /search & /memories ┌──────────────────┐
│ AI agent / │ ──── X-Api-Key + JSON ───────▶ │ mem0 API :20015 │
│ Hermes / bot │ └────────┬─────────┘
└──────────────┘ │ pgvector
PostgreSQL 17 + pgvector
┌──────────────┐ model calls (extract) ┌──────────────────┐
│ OpenAI etc. │ ◀───────── LiteLLM ──────────│ fact-classifier │
└──────────────┘ └──────────────────┘
```
一份有代表性的 compose 长这样:
```yaml
services:
mem0-postgres:
image: pgvector/pgvector:pg17
environment:
POSTGRES_USER: mem0
POSTGRES_PASSWORD: ${MEM0_DB_PASSWORD}
POSTGRES_DB: mem0
volumes:
- ./data/pg:/var/lib/postgresql/data
restart: unless-stopped
mem0-litellm:
image: ghcr.io/berriai/litellm:main-stable
command: ["--config", "/app/config.yaml"]
volumes:
- ./litellm-config.yaml:/app/config.yaml
restart: unless-stopped
mem0-api:
build: ./mem0-api
environment:
OPENAI_API_KEY: ${OPENAI_API_KEY}
OPENAI_API_BASE: http://mem0-litellm:4000/v1 # go through the gateway
MEM0_API_KEY: ${MEM0_API_KEY} # X-Api-Key for /search & /memories
POSTGRES_URL: postgresql://mem0:${MEM0_DB_PASSWORD}@mem0-postgres/mem0
ports:
- "20015:8000"
restart: unless-stopped
```
(我是从 mem0 仓库本地构建、把模型/事实抽取指向 LiteLLM;确切的镜像版本是我自己维护本地镜像的结果。真实 API key 我放在 compose 文件外面,走环境变量密文注入。)
## 使用
起起来之后,这个 API 小到意外。加一条事实(快速、逐字保存):
```bash
curl -X POST http://192.168.1.1:20015/memories \
-H "Content-Type: application/json" \
-H "X-Api-Key: $MEM0_API_KEY" \
-d '{
"user_id": "customer-2211",
"text": "Customer 2211 prefers email over WhatsApp for order updates."
}'
```
之后再取最相关的记忆:
```bash
curl -X POST http://192.168.1.1:20015/memories/search \
-H "Content-Type: application/json" \
-H "X-Api-Key: $MEM0_API_KEY" \
-d '{
"user_id": "customer-2211",
"query": "how should I reach this customer?",
"limit": 5
}'
```
然后把返回的事实塞进助手回答前的系统提示词(或上下文)。这就是全部循环:**存事实、召回相关的、在下一句回复里用上。**
### 让我花了一天时间的 `infer` 坑
- `POST /memories` 默认 **`infer=true`** 会跑 LLM 事实抽取器——分类、清洗每条记忆。聪明但**慢**,而且每次调用都要一次模型往返。
- 如果我只是想让助手**逐字快速地**记下某件事(客户说「请叫我 Andy」),我传 **`infer=false`**——不经过 LLM,近乎瞬时存储。
我栈上的路由是 `/search``/memories`**没有 `/v1` 前缀**(早期一个自以为有 `/v1` 的包装器 404 了一阵子),认证是朴实的 `X-Api-Key` 头。都是小事,但都让我费过时间。
## 如果重来我会怎么做
- **从第一天起对常规记录就用 `infer=false`。** 只对重要的事实跑 LLM 抽取;默认的推理模式让每一次写入都为了一句随手记付出的成本不值。
- **把 API key 当真正的机密。** 它会嵌进 agent 配置和 compose 环境变量里,所以我把它从 compose 文件中拿出来,用环境密文注入。
- **把数据库放在我信任的盘上。** Mem0 的下限就是你 Postgres 的下限。我把它跑在 NAS 受保护的卷上、带备份任务——因为一个会失忆的记忆层还不如没有。
## 结果
一层私有、自托管的记忆,用两个小 HTTP 调用就能访问。我的助手现在跨会话记得客户、偏好和决策——而且因为整个栈都在我自己网络后面的 PostgreSQL 里,这一切都没有离开我的掌控。
如果你跑的 AI 助手动不动就忘掉上下文,自托管 mem0 是最划算、最省事的升级之一——而且你能在不把记忆送进别人数据库的前提下做到。
---
## 想让你的生意也用上带记忆的 AI 吗?
我为企业构建并自托管 AI 助手、记忆栈、网站和基础设施。如果你想让助手真正**记住**你的客户——或者你想聊聊雇佣我——我很乐意帮上忙:
- 📱 **WhatsApp** [+60 12-797 2969](https://wa.me/60127972969)
- 📧 **邮箱:** [[email protected]](mailto:[email protected])
- 🌐 **网站:** [hoelee.com](https://hoelee.com)
@@ -0,0 +1,97 @@
---
title: "SMART 显示健康,RAID 却在悄悄损坏数据"
description: "两块看起来完全健康的 NVMe 组成的 btrfs RAID1 阵列,却静默地把 Windows 虚拟机喂成了全零字节。我如何抓住它、靠校验和取证证明它,以及为什么最终要把两块盘都换掉。"
pubDate: 2026-09-16
category: devops
tags: [unraid, btrfs, nvme, raid, storage, data-loss, troubleshooting]
ogImage: /og/when-smart-says-healthy-but-your-raid-is-corrupting-data.png
banner: /banners/when-smart-says-healthy-but-your-raid-is-corrupting-data.png
---
所有存储指南都告诉你同一件事:相信 SMART、检查事件日志、相信你的文件系统。我的硬件不这么想。2026 年 9 月,一个 btrfs RAID1 阵列——两块企业级 NVMe 盘镜像,我用每个能想到的工具查它都说**「健康」**——却在悄悄地把我的 Windows 11 虚拟机喂成全零字节。不是看得见的故障,是静默损坏。
下面是完整故事:损坏是怎么浮现的、哪个校验和出卖了它、以及为什么答案必须是「两块盘都换,别信 SMART」。
## 为什么这件事重要
损坏状态的磁盘是最糟的存储故障,因为它最容易漏掉:
- **SMART 看起来完美。** 零媒体错误、几乎满余量,而且是能扛企业级写入负载的盘。
- **阵列有冗余。** btrfs RAID1 把每个块镜像到两块盘上。当**两个成员**用同一种方式撒谎时,冗余毫无意义。
- **故障是静默的。** 数组状态没有红色警告、没有硬盘报错、没有硬件事件——只有虚拟机读回垃圾,直到备份恢复成了唯一的选择。
如果你的数据在一切看起来都正常的时候悄悄坏掉,「备份」就不是偏执——它是全部。这次事故让我明白:一条**可测试、可验证的恢复**胜过任何阵列状态屏幕。
## 环境
- **unRaid 7.x**Intel i9-13900KWindows 11 虚拟机是主力工作站(GPU 直通)。
- **缓存池:** 两块 **Samsung PM9A3 3.84TB** NVMe 组 **btrfs RAID1**。而且两块是**同一生产批次**(同一个控制器/固件版本 `GDC7702Q`)。
- Windows 虚拟机的虚拟磁盘(`vdisk1.img``vdisk2.img`)就在这个池的 `domains/` 共享里,另外还有 **Docker 数据根目录**
- 虚拟磁盘**没有**设 `NOCOW`——所以每次读取都会被 btrfs 校验和验证。也正因为这个,我最后才抓得住它。
## 症状
我开始发现缓存读取慢得离谱,主机命令也卡住:`cat`、读 `/proc/loadavg`、甚至 `docker image ls` 都在超时。那块坏 NVMe 正以 **4575 MB/s** 被狂读,每次读都塞满整台主机的 I/O。本该几秒跑完的 `docker system prune` 直接挂死。
然后真正的麻烦来了:Windows 虚拟机开始狂报读错误,回来的是**错的**数据——满文件的全零字节、guest 里的校验和失败,最后主力 VM 直接引导不了。
## 取证:`csum 0x8941f998`
btrfs 在读校验失败时会往内核日志记一条校验和不匹配。同一个值反复出现:
```text
btrfs: checksum verify failed on <device> wanted 0x8941f998 found <other>
```
这个特定值是最重要的线索。**`0x8941f998` 就是一整块零字节的 CRC32C。** 它每次都出现、跨越互不相关的文件和 inode,绝不是巧合。正在发生的不是随机比特腐烂,而是盘**稳定地返回全零块**,而这些零填充的读取正是 btrfs 校验失败的对象:
- 验证一下:零填充块的 `crc32c` 就等于 `0x8941f998`
- 同一个值反复出现 → 读取是**确定性**地吐出空数据,不是偶尔翻几个比特。
两块虚拟磁盘都中招(`vdisk1.img` inode 2358574、`vdisk2.img` inode 2362817),正好对上「存储层在把零当成被请求的数据返回」的图景。
## 破绽:永远不生效的「自愈」
btrfs RAID1 本应自愈:一个成员坏块、从镜像重建、写回好数据。但我一遍遍 scrub、重读同一块(仍然全零的)数据后发现,**重写根本不落地**。每次重建「成功」后,立刻重读同一 extent 又吐出零。
这是关键区别:
- 一块**只读不出来**的盘是读问题——自愈应该能从镜像救回来。
- 一块**连回调也无脑吞垃圾存进去**的盘是**写或控制器**问题——镜像救不了你,因为两条路径都对同一个错误答案达成一致。
当自愈重写一直不生效,你就不在「坏一个扇区」的范畴了,而是「这块盘在写入上撒谎」——RAID 冗余救不了。
## 为什么两块盘都得换
数据指向的是**同批次盘的硬件缺陷**,而不是磨损或一次性的偶发事件:
- SMART 干净(0 媒体错误、几乎满余量,`nvme0` 大约写了 586 TiB——对能扛企业级负载的盘来说算重负载但仍正常)。
- 两块盘**同批次、同控制器/固件**(`GDC7702Q`)。
- 损坏以**相关的方式**同时命中两个 RAID1 成员——镜像「死一块也能幸存」的整个意义,因为两块盘正以同一种方式一起死掉而完全失效。
面对批次级的关联缺陷,留下那块「看起来健康」的盘当幸存成员是假省心。**我从备份恢复了 Windows 虚拟机,然后把两块盘都换掉。**
## 我同时做的事:把数据迁出那个池
在换盘之前,任何还值得读的数据都得搬出这个坏池——而且要**验证**,不能想当然:
- **Docker 数据根目录**迁出缓存:`docker` 挪到 `/mnt/user/docker`(在 `disk1` 上,overlay2)。整棵树通过**路径、大小、mtime** 逐文件比对、并与字节对比交叉验证,共 **3,997,569** 个文件。
- 缓存的 `isos/``system/``swapfile` 搬到 `disk1``isos/`(约 13 GB)用 `diff -rq` 检查 → **EXIT=0**,无差异。
- 所有搬走的文件都在**删除缓存副本之前**先跟源比对过——没验证过的副本绝不删。
因为存在读侧损坏(全零块)和写侧损坏(自愈不落地),那个池里的任何东西,没有镜像、没有校验和、没有新鲜备份可对照,我就一律不信任。
## 如果重来我会怎么做
1. **在需要它之前就先测试恢复虚拟机备份。** 我当时确认了备份存在,但损坏事故不是该第一次学恢复流程的时候。定时做的测试恢复既能发现备份问题,也能发现静默的存储损坏。
2. **把同批次的两块盘当成一块盘。** 两块 PM9A3 同批次同固件。对需要长期搭档的缓存池(任何 RAID1)这是关联失效风险——优先选不同批次的盘,或者至少在信任镜像前把这对盘狠狠测一遍。
3. **主动检测,而不是被动祈祷。** 正是 btrfs 校验和让它在噪声里浮出来。不开 `NOCOW` 意味着文件系统在验证每一次读取;一个带校验的数据池,就是「当场抓住并恢复」和「把损坏文件带出去几个月」之间的分水岭。
4. **别用 SMART 判断闪存。** 一块看起来健康却照样损坏的 NVMe,事件计数什么也说明不了——固件级的缺陷可以躲过所有 SMART 属性。
## 结果
一台 Windows 虚拟机从备份恢复、两块确认故障的盘换掉、Docker 数据根目录安全迁出该池。代价是几天折腾和一次救援——但损失被控制在最小,因为损坏是被校验和抓住的,而不是在里面泡了几个星期。
最该记住的一句话:**对存储来说,「冗余」只等于你最不靠谱的那个成员。** 两块一起坏掉的盘不是镜像——那是穿着两个序列号的单点故障。验证你的恢复、校验你的数据、当某块盘的零块「奖励」反复出现时,把整组都换掉。
---