@@ -1,6 +1,6 @@

 <!-- [metadata]>

 +++

-title = "Using the command line"

+title = "Docker Engine Commands"

 description = "Docker's CLI command description and usage"

 keywords = ["Docker, Docker documentation, CLI,  command line"]

 [menu.main]

@@ -12,7 +12,7 @@ parent = "mn_reference"

 # The Docker commands

-This section contains reference information on using Docker's command line client. Each command has a reference page along with samples. If you are unfamiliar with the command line, you should start by reading about how to ["Use the Docker command line"](cli.md).  

+This section contains reference information on using Docker's command line client. Each command has a reference page along with samples. If you are unfamiliar with the command line, you should start by reading about how to [Use the Docker command line](cli.md).  

 You start the Docker daemon with the command line. How you start the daemon affects your Docker containers. For that reason you should also make sure to read the [`daemon`](daemon.md) reference page.

@@ -210,18 +210,20 @@ The procedure below will create a 90GB data volume and 4GB metadata volume to us

 5. Start the Docker daemon with the `devicemapper` storage driver and the `--storage-opt` flags.

-  The `data` and `metadata` devices that you pass to the `--storage-opt` options were created in the previous steps.

-

-        $ sudo docker daemon --storage-driver=devicemapper --storage-opt dm.datadev=/dev/vg-docker/data --storage-opt dm.metadatadev=/dev/vg-docker/metadata &

-        [1] 2163

-        [root@ip-10-0-0-75 centos]# INFO[0000] Listening for HTTP on unix (/var/run/docker.sock)

-        INFO[0027] Option DefaultDriver: bridge

-        INFO[0027] Option DefaultNetwork: bridge

-        <output truncated>

-        INFO[0027] Daemon has completed initialization

-        INFO[0027] Docker daemon                                 commit=0a8c2e3 execdriver=native-0.2 graphdriver=devicemapper version=1.8.2

-

-    It is also possible to set the `--storage-driver` and `--storage-opt` flags in the Docker config file and start the daemon normally using the `service` or `systemd` commands.

+    The `data` and `metadata` devices that you pass to the `--storage-opt` options were created in the previous steps.

+

+          $ sudo docker daemon --storage-driver=devicemapper --storage-opt dm.datadev=/dev/vg-docker/data --storage-opt dm.metadatadev=/dev/vg-docker/metadata &

+          [1] 2163

+          [root@ip-10-0-0-75 centos]# INFO[0000] Listening for HTTP on unix (/var/run/docker.sock)

+          INFO[0027] Option DefaultDriver: bridge

+          INFO[0027] Option DefaultNetwork: bridge

+          <output truncated>

+          INFO[0027] Daemon has completed initialization

+          INFO[0027] Docker daemon commit=0a8c2e3 execdriver=native-0.2 graphdriver=devicemapper version=1.8.2

+

+    It is also possible to set the `--storage-driver` and `--storage-opt` flags in

+    the Docker config file and start the daemon normally using the `service` or

+    `systemd` commands.

 6. Use the `docker info` command to verify that the daemon is using `data` and `metadata` devices you created.

@@ -137,7 +137,7 @@ Once ZFS is installed and loaded, you're ready to configure ZFS for Docker.

         $ sudo zpool create -f zpool-docker /dev/xvdb

-  The command creates the `zpool` and gives it the name "zpool-docker". The name is arbitrary.

+    The command creates the `zpool` and gives it the name "zpool-docker". The name is arbitrary.

 2. Check that the `zpool` exists.

@@ -156,7 +156,7 @@ Once ZFS is installed and loaded, you're ready to configure ZFS for Docker.

         zpool-docker         93.5K  3.84G    19K  /zpool-docker

         zpool-docker/docker  19K    3.84G    19K  /var/lib/docker

-  Now that you have a ZFS filesystem mounted to `/var/lib/docker`, the daemon should automatically load with the `zfs` storage driver.

+    Now that you have a ZFS filesystem mounted to `/var/lib/docker`, the daemon should automatically load with the `zfs` storage driver.

 5. Start the Docker daemon.

@@ -185,9 +185,9 @@ Once ZFS is installed and loaded, you're ready to configure ZFS for Docker.

         Execution Driver: native-0.2

         [...]

-  The output of the command above shows that the Docker daemon is using the

-  `zfs` storage driver and that the parent dataset is the `zpool-docker/docker`

-  filesystem created earlier.

+    The output of the command above shows that the Docker daemon is using the

+    `zfs` storage driver and that the parent dataset is the `zpool-docker/docker`

+    filesystem created earlier.

 Your Docker host is now using ZFS to store to manage its images and containers.

@@ -207,7 +207,7 @@ using them with ZFS.

 * **ZFS Caching**. ZFS caches disk blocks in a memory structure called the adaptive replacement cache (ARC). The *Single Copy ARC* feature of ZFS allows a single cached copy of a block to be shared by multiple clones of a filesystem. This means that multiple running containers can share a single copy of cached block. This means that ZFS is a good option for PaaS and other high density use cases.

-- **Fragmentation**. Fragmentation is a natural byproduct of copy-on-write filesystems like ZFS. However, ZFS writes in 128K blocks and allocates *slabs* (multiple 128K blocks) to CoW operations in an attempt to reduce fragmentation. The ZFS intent log (ZIL) and the coalescing of writes (delayed writes) also help to reduce fragmentation. 

+- **Fragmentation**. Fragmentation is a natural byproduct of copy-on-write filesystems like ZFS. However, ZFS writes in 128K blocks and allocates *slabs* (multiple 128K blocks) to CoW operations in an attempt to reduce fragmentation. The ZFS intent log (ZIL) and the coalescing of writes (delayed writes) also help to reduce fragmentation.

 - **Use the native ZFS driver for Linux**. Although the Docker `zfs` storage driver supports the ZFS FUSE implementation, it is not recommended when high performance is required. The native ZFS on Linux driver tends to perform better than the FUSE implementation.