Vault setup with file storage but no file is created

Hi, I am learning hashicorp vault with. I have this configuration and I run vault in a container:

listener "tcp" {
  address     = "0.0.0.0:8200"
  tls_disable = 1
}

storage "file" {
  path  = "/vault/file"
}

Vault container starts and I can store some keys in there but the folder /vault/file is empty…

These are the logs:

==> Vault server configuration:

                     Cgo: disabled
              Go Version: go1.14.7
              Listener 1: tcp (addr: "0.0.0.0:8200", cluster address: "0.0.0.0:8201", max_request_duration: "1m30s", max_request_size: "33554432", tls: "disabled")
               Log Level: info
                   Mlock: supported: true, enabled: true
           Recovery Mode: false
                 Storage: file
                 Version: Vault v1.5.4
             Version Sha: 1a730771ec70149293efe91e1d283b10d255c6d1

==> Vault server started! Log data will stream in below:

2020-10-20T20:56:50.272Z [INFO]  proxy environment: http_proxy= https_proxy= no_proxy=
2020-10-20T20:56:50.272Z [WARN]  no `api_addr` value specified in config or in VAULT_API_ADDR; falling back to detection if possible, but this value should be manually set
2020-10-20T20:56:50.852Z [INFO]  core: security barrier not initialized
2020-10-20T20:58:13.293Z [INFO]  core: seal configuration missing, not initialized
2020-10-20T20:58:38.224Z [INFO]  core: security barrier not initialized
2020-10-20T20:58:38.225Z [INFO]  core: security barrier initialized: stored=1 shares=1 threshold=1
2020-10-20T20:58:38.227Z [INFO]  core: post-unseal setup starting
2020-10-20T20:58:38.240Z [INFO]  core: loaded wrapping token key
2020-10-20T20:58:38.240Z [INFO]  core: successfully setup plugin catalog: plugin-directory=
2020-10-20T20:58:38.240Z [INFO]  core: no mounts; adding default mount table
2020-10-20T20:58:38.243Z [INFO]  core: successfully mounted backend: type=cubbyhole path=cubbyhole/
2020-10-20T20:58:38.244Z [INFO]  core: successfully mounted backend: type=system path=sys/
2020-10-20T20:58:38.244Z [INFO]  core: successfully mounted backend: type=identity path=identity/
2020-10-20T20:58:38.247Z [INFO]  core: successfully enabled credential backend: type=token path=token/
2020-10-20T20:58:38.247Z [INFO]  core: restoring leases
2020-10-20T20:58:38.248Z [INFO]  rollback: starting rollback manager
2020-10-20T20:58:38.248Z [INFO]  expiration: lease restore complete
2020-10-20T20:58:38.248Z [INFO]  identity: entities restored
2020-10-20T20:58:38.248Z [INFO]  identity: groups restored
2020-10-20T20:58:38.249Z [INFO]  core: post-unseal setup complete
2020-10-20T20:58:38.249Z [INFO]  core: root token generated
2020-10-20T20:58:38.249Z [INFO]  core: pre-seal teardown starting
2020-10-20T20:58:38.249Z [INFO]  rollback: stopping rollback manager
2020-10-20T20:58:38.249Z [INFO]  core: pre-seal teardown complete
2020-10-20T20:58:38.249Z [INFO]  core: usage gauge collection is disabled
2020-10-20T20:59:51.336Z [INFO]  core.cluster-listener.tcp: starting listener: listener_address=0.0.0.0:8201
2020-10-20T20:59:51.338Z [INFO]  core.cluster-listener: serving cluster requests: cluster_listen_address=[::]:8201
2020-10-20T20:59:51.338Z [INFO]  core: post-unseal setup starting
2020-10-20T20:59:51.339Z [INFO]  core: loaded wrapping token key
2020-10-20T20:59:51.339Z [INFO]  core: successfully setup plugin catalog: plugin-directory=
2020-10-20T20:59:51.340Z [INFO]  core: successfully mounted backend: type=system path=sys/
2020-10-20T20:59:51.341Z [INFO]  core: successfully mounted backend: type=identity path=identity/
2020-10-20T20:59:51.341Z [INFO]  core: successfully mounted backend: type=cubbyhole path=cubbyhole/
2020-10-20T20:59:51.344Z [INFO]  core: successfully enabled credential backend: type=token path=token/
2020-10-20T20:59:51.344Z [INFO]  core: restoring leases
2020-10-20T20:59:51.345Z [INFO]  rollback: starting rollback manager
2020-10-20T20:59:51.345Z [INFO]  identity: entities restored
2020-10-20T20:59:51.345Z [INFO]  identity: groups restored
2020-10-20T20:59:51.345Z [INFO]  core: post-unseal setup complete
2020-10-20T20:59:51.345Z [INFO]  core: vault is unsealed
2020-10-20T20:59:51.345Z [INFO]  expiration: lease restore complete
2020-10-20T20:59:51.345Z [INFO]  core: usage gauge collection is disabled
2020-10-20T21:00:12.131Z [INFO]  core: successful mount: namespace= path=test/ type=kv

Any idea why vault is not storing my keys in disk?

thank you
Manuel