# Docker Storage

> Guidance for Docker storage and data persistence. Covers storage types (Volume/Bind Mount/Tmpfs) with comparison and use-case selection, volume lifecycle management (create/ls/inspect/prune), bind mount patterns, tmpfs for ephemeral data, backup and restore strategies, storage driver selection (overlay2), database persistence best practices (PostgreSQL/MySQL/Redis), and NFS/cloud storage integration. Use when the user asks about docker volume, data persistence, bind mount, tmpfs, storage driver, backup, data volume, or needs persistent storage for containers. 使用场景：docker volume、数据持久化、bind mount、tmpfs、存储驱动、数据卷、备份恢复、数据库持久化.

- Skill: `full-stack-skills/docker-storage` (Agent Skill, multi-file: 6 files)
- Install (CLI): `npx skillmds@latest add full-stack-skills/docker-storage`
- Raw SKILL.md: https://api.skillmd.com/api/skills/full-stack-skills/docker-storage/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: DevOps & Infra
- License: Apache-2.0
- Author: full-stack-skills (https://skillmd.com/u/full-stack-skills)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/full-stack-skills/docker-storage

---


# Docker Storage — 存储与数据持久化

Comprehensive guidance for managing persistent data in Docker.

## When to Use

**ALWAYS use this skill when the user mentions:**
- "docker volume", "数据卷", "数据持久化"
- "bind mount", "tmpfs"
- "容器数据怎么保存", "数据不丢失"
- "数据库容器怎么持久化"
- "备份恢复", "存储驱动"

## Storage Type Comparison

| Type | Persistence | Performance | Use Case |
|------|:--:|:--:|------|
| **Volume** | ✅ (managed by Docker) | High (native) | Production databases, shared data |
| **Bind Mount** | ✅ (host filesystem) | High | Development (live code sync), config files |
| **Tmpfs** | ❌ (memory only) | Highest | Secrets, temp files, sensitive data |

### Visual Comparison

```
Volume:                       Bind Mount:               Tmpfs:
  Container                     Container                 Container
     │                              │                        │
  Docker-managed               /host/path                 Memory only
  /var/lib/docker/volumes/        ↕                     (no disk)
     ↕                         Container sees:              ↕
  Container sees:              /container/path           Container sees:
  /data                         = host files              /tmp (in RAM)
```

## Volume Management

```bash
# Create & inspect
docker volume create mydata
docker volume ls
docker volume inspect mydata

# Use in container
docker run -v mydata:/var/lib/mysql mysql:8
docker run --mount source=mydata,target=/var/lib/mysql mysql:8  # explicit syntax (recommended)

# Cleanup
docker volume prune      # Remove unused volumes
docker volume rm mydata  # Remove specific volume
```

### Named vs Anonymous Volumes

```
-v mydata:/data      → Named volume  (mydata) — survives container removal ✅
-v /data             → Anonymous volume — hard to identify later ❌
```

## Bind Mount

```bash
# Read-write bind mount
docker run -v $(pwd)/app:/app nginx

# Read-only (protect host files)
docker run -v $(pwd)/config:/etc/nginx:ro nginx

# Explicit syntax
docker run --mount type=bind,source=$(pwd)/app,target=/app nginx
```

## Tmpfs (Memory)

```bash
# Ephemeral data, never touches disk
docker run --tmpfs /tmp:rw,noexec,nosuid,size=64m nginx
docker run --mount type=tmpfs,destination=/tmp,tmpfs-size=64m nginx
```

## Database Persistence Patterns

### PostgreSQL

```bash
docker volume create pgdata
docker run -d \
  --name postgres \
  -e POSTGRES_PASSWORD=secret \
  -v pgdata:/var/lib/postgresql/data \
  -p 5432:5432 \
  postgres:16-alpine
```

### MySQL

```bash
docker volume create mysqldata
docker run -d \
  --name mysql \
  -e MYSQL_ROOT_PASSWORD=secret \
  -v mysqldata:/var/lib/mysql \
  -v $(pwd)/my.cnf:/etc/mysql/conf.d/my.cnf:ro \
  -p 3306:3306 \
  mysql:8.4
```

### Redis (Persistence)

```bash
docker volume create redisdata
docker run -d \
  --name redis \
  -v redisdata:/data \
  -p 6379:6379 \
  redis:7-alpine redis-server --appendonly yes
```

## Backup & Restore

```bash
# Backup (using a temporary container)
docker run --rm \
  -v mysqldata:/source \
  -v $(pwd):/backup \
  alpine tar czf /backup/mysqldata-backup.tar.gz -C /source .

# Restore
docker run --rm \
  -v mysqldata:/target \
  -v $(pwd):/backup \
  alpine tar xzf /backup/mysqldata-backup.tar.gz -C /target
```

## Storage Drivers

| Driver | Status | Notes |
|--------|:--:|------|
| **overlay2** | ✅ Default | Best for most use cases; copy-on-write |
| devicemapper | Deprecated | - |
| aufs | Deprecated | - |
| btrfs/zfs | Niche | Use if filesystem matches |

```bash
docker info | grep "Storage Driver"  # Check current
```

## Workflow — 推荐配置流程

Step 1: **确定存储类型**: 持久化数据 → Volume；开发热加载 → Bind Mount；临时缓存 → tmpfs
Step 2: **创建 Volume**: `docker volume create db_data`
Step 3: **挂载到容器**: `docker run -v db_data:/var/lib/mysql mysql`
Step 4: **验证**: `docker volume inspect db_data` + `docker exec mysql ls /var/lib/mysql`
Step 5: **备份**: `docker run --rm -v db_data:/source -v $(pwd):/backup alpine tar czf /backup/db.tar.gz -C /source .`

## Gotchas — Common Pitfalls

- **Anonymous volumes accumulate**: Every `-v /data` (no name) creates a new anonymous volume. → **Recovery**: `docker volume prune` cleans all unused; use named volumes: `-v mydata:/data`.
- **Bind mount paths**: Must be absolute. → **Recovery**: `-v $(pwd)/app:/app` for docker run; `-v ./app:/app` works in Compose only.
- **Permission issues with bind mounts**: Container UID != host UID → permission denied. → **Recovery**: `--user $(id -u):$(id -g)` or `RUN chown 1000:1000 /data` in Dockerfile entrypoint.
- **Data loss on container removal**: Without `-v`, data is lost when container is removed. `--rm` flag even worse. → **Recovery**: Always use named volumes: `docker run -v db_data:/var/lib/mysql`.
- **macOS bind mount performance**: Bind mounts on Docker Desktop Mac are slow. → **Recovery**: Use `:cached` or `:delegated` mount options, or named volumes for better I/O.

## Boundary — 能力边界（适用与不适用场景）

| 分类 | 场景 | 说明 |
|------|------|------|
| ✅ 能做 | 数据持久化配置（Volume/Bind Mount/tmpfs） | 三类存储的创建、挂载、管理 |
| ✅ 能做 | 备份与恢复 | `tar` + `--volumes-from` 备份恢复 |
| ✅ 能做 | 存储驱动选型 | overlay2/btrfs/zfs 对比 |
| ⚠️ 需条件 | NFS/云存储 Volume 驱动 | 需安装对应驱动插件 |
| ⚠️ 需条件 | macOS 下 Bind Mount 性能 | 使用 `:cached`/`:delegated` 或命名 Volume |
| ❌ 超范围 | K8s PersistentVolume/PVC | 使用 `docker-production` + K8s 文档 |
| ❌ 超范围 | 分布式文件系统（Ceph/GlusterFS） | 系统管理员范畴 |
| ❌ 超范围 | 数据库性能优化 | DBA 专业领域 |

## When NOT to Use This Skill

| ❌ Skip | ✅ Use Instead |
|---------|---------------|
| Running containers (no data concerns) | `docker-run` |
| Multi-container orchestration | `docker-compose` |
| Kubernetes Storage (PV/PVC) | K8s documentation |
| Docker basics | `docker-basics` |

## Security & Stability

- Use `:ro` for config files that containers should not modify.
- Never bind mount Docker socket (`/var/run/docker.sock`) without understanding the security implications.
- Backup volumes regularly, especially database volumes.
- No executable scripts bundled. Guidance only.

## 📚 官方文档参考

| 文档 | 地址 |
|------|------|
| Docker 存储 | https://docs.docker.com/storage/ |
| Volumes | https://docs.docker.com/storage/volumes/ |
| Bind Mounts | https://docs.docker.com/storage/bind-mounts/ |
| tmpfs | https://docs.docker.com/storage/tmpfs/ |
| 存储驱动 | https://docs.docker.com/storage/storagedriver/ |
| docker volume 命令 | https://docs.docker.com/reference/cli/docker/volume/ |

## 🧭 Docker Skills Journey

> 📍 **You are here: `docker-storage` — 数据持久化**

**← Previous**: `docker-run` / `docker-networking`
**→ Next**: `docker-compose` / `docker-security`

## FAQ

**Q1: 如何快速上手此技能？**
A: 参考上方的快速开始章节，按步骤操作即可。

**Q2: 遇到版本不兼容问题怎么办？**
A: 检查依赖版本，使用 lock 文件锁定，参考常见陷阱章节。

**Q3: 如何在生产环境使用？**
A: 参考最佳实践章节，确保配置正确，做好监控和日志。

**Q4: 性能如何优化？**
A: 参考性能优化相关文档，使用缓存、索引等手段。

**Q5: 如何贡献或反馈问题？**
A: 在 GitHub 仓库提交 Issue 或 Pull Request。

**Q6: 是否支持中文？**
A: 支持中文文档和中文注释，详见国内适配章节。