Volumes & Storage

docker volume create <name>
docker run -v <name>:<container_path> <image>

docker volume create pgdata
docker run -d -v pgdata:/var/lib/postgresql/data postgres:16

pgdata

Note Named volumes are managed by Docker and stored under /var/lib/docker/volumes/ on Linux. They persist independently of containers and survive docker rm. This is the recommended way to persist database data.

docker run -v <host_path>:<container_path>[:<options>] <image>
docker run --mount type=bind,source=<path>,target=<path> <image>

docker run -v $(pwd)/src:/app/src myapp:1.0
docker run --mount type=bind,source=$(pwd)/config,target=/app/config,readonly myapp:1.0

Note Bind mounts give the container direct access to host files — changes are reflected immediately in both directions. On macOS and Windows, bind mount performance can be noticeably slow for large node_modules directories.

docker run --tmpfs <container_path>[:<options>] <image>
docker run --mount type=tmpfs,target=<path> <image>

docker run -d --tmpfs /tmp:rw,noexec,size=100m myapp:1.0
docker run -d --mount type=tmpfs,target=/app/cache,tmpfs-size=67108864 myapp:1.0

Note Data is stored in memory and disappears when the container stops. Use for sensitive data (secrets, tokens) that should never be written to disk, or for scratch space where speed matters more than persistence.

docker volume inspect <name>

docker volume inspect pgdata

[
  {
    "Name": "pgdata",
    "Driver": "local",
    "Mountpoint": "/var/lib/docker/volumes/pgdata/_data",
    "CreatedAt": "2025-11-15T10:30:00Z"
  }
]

Note The Mountpoint shows where the data lives on the host filesystem. On Docker Desktop (macOS/Windows), this path is inside the Linux VM, not directly accessible from your host.

docker volume ls
docker volume rm <name>
docker volume prune

docker volume ls
docker volume rm pgdata
docker volume prune

DRIVER    VOLUME NAME
local     pgdata
local     redis-data
local     a1b2c3d4e5f6...

Note docker volume prune removes ALL volumes not used by any container. This destroys data permanently with no undo. The long hex-named volumes are anonymous volumes — usually safe to remove, but verify first.

docker run --rm -v <volume>:/source -v $(pwd):/backup <image> tar czf /backup/<file>.tar.gz -C /source .

docker run --rm \
  -v pgdata:/source:ro \
  -v $(pwd):/backup \
  alpine:3.19 \
  tar czf /backup/pgdata-backup.tar.gz -C /source .

Note This spins up a temporary Alpine container that mounts the volume read-only and your current directory, then creates a compressed tar archive. To restore, reverse the process by extracting the tar into a new volume.

docker run -v <container_path> <image>
# or VOLUME in Dockerfile

docker run -d -v /var/cache myapp:1.0
# Creates an anonymous volume with a random hex name

Note Anonymous volumes get a random hash name and are easy to lose track of. They accumulate over time and waste disk space. Prefer named volumes so you can identify and manage your data. Use docker volume prune periodically to clean up orphans.