Notice

This document is for a development version of Ceph.

Block Device Quick Start

Ensure your Ceph Storage Cluster is in an active + clean state before working with the Ceph Block Device.

Note

The Ceph Block Device is also known as RBD or RADOS Block Device.

You may use a virtual machine for your ceph-client node, but do not execute the following procedures on the same physical node as your Ceph Storage Cluster nodes (unless you use a VM). See FAQ for details.

Create a Block Device Pool

  1. On the admin node, use the ceph tool to create a pool (we recommend the name ‘rbd’).

  2. On the admin node, use the rbd tool to initialize the pool for use by RBD:

    rbd pool init <pool-name>
    

Configure a Block Device

  1. On the ceph-client node, create a block device image.

    rbd create foo --size 4096 --image-feature layering [-m {mon-IP}] [-k /path/to/ceph.client.admin.keyring] [-p {pool-name}]
    
  2. On the ceph-client node, map the image to a block device.

    sudo rbd map foo --name client.admin [-m {mon-IP}] [-k /path/to/ceph.client.admin.keyring] [-p {pool-name}]
    
  3. Use the block device by creating a file system on the ceph-client node.

    sudo mkfs.ext4 -m0 /dev/rbd/{pool-name}/foo
    
    This may take a few moments.
    
  4. Mount the file system on the ceph-client node.

    sudo mkdir /mnt/ceph-block-device
    sudo mount /dev/rbd/{pool-name}/foo /mnt/ceph-block-device
    cd /mnt/ceph-block-device
    
  5. Optionally configure the block device to be automatically mapped and mounted at boot (and unmounted/unmapped at shutdown) - see the rbdmap manpage.

See block devices for additional details.