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
# 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
# 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)
# 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
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
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)
docker volume create redisdata
docker run -d \
--name redis \
-v redisdata:/data \
-p 6379:6379 \
redis:7-alpine redis-server --appendonly yes
Backup & Restore
# 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 |
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
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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。